From going from a 2000 kx250 , to a 2023 kx450x, wow what a huge change in performance and technology. Got bike home and completely tore it down to just engine in chassis, lubed and greased everything and retorquorted everything to spec . But watching your videos on the multiple sensors and ohms check really gives me a peace of mind! Thanks alot for your info
Thank you for your feedback and support. You’re certainly not the kind of guy I buy my bikes from (they don’t even change the oil). Good luck with your new bike and ride safe.
I now understand your channel and what you do , I'm very impressed and i love to learn something new everyday. I've probably watched now 8 or 10 of your videos today . Always something new to learn from you. I'm a tincker , my wife about shit herself, when she opened the garage door up yesterday and saw a new kx450x in a hundred pieces. Lol i blamed you.
I have a 14 kx450 also and I replaced the fuel pump filter and it ran fine but I rode it for about 20 mins and shut it off and then it wouldn’t start again. The only way I can get it to start now is if I hook up a 12v battery to the capacitor connector or kick it like 50 times. I replaced the capacitor but that didn’t do anything and the stator is .1 over spec and the ignition coil is .5 over spec for the primary and secondary is in spec. The valves were adjusted about 5 hours ago
Have you checked ALL three stator coils across each other and to ground? If all of those coils check out ok, I would do a fuel pressure check. I wouldn't worry about the coil because it runs. Sounds like a fuel pressure issue either due to a leak or bypass in the pump module/regulator or the stator is not providing enough power to run the pump during kicking.
I got a 16 kx 450 bike was running super lean and backfiring not really hard to start but I did valve adjustment and new fuel filter and now the bike doesn’t want to start at all valves are all in spec and timings spot on
If you’re 100% sure that the timing is correct, and the valve clearances are correct, pull the fuel line off of the tank, hook a piece of rubber hose to the pump and into a bucket. Give it a few kicks to see what kind of fuel flow you have. Ideally, you would want to do a fuel pressure test. I have a newer video out on replacing the timing chain and it goes over the timing marks if you’d like to look at that as a back up.
@@nickmee3321 black smoke is representative of a rich condition, blue would be oil burning and white is condensation or water burning. Is it showing black smoke in all riding conditions or just when on the throttle?
On the newer bikes, sometimes people don’t want the air forks so they will use spring forks from another bike. I certainly can’t speculate why someone changed the forks on your 07.
Wow thanks my my gear position sensor is bad the actual first sensor I’ve seen go bad through my own testing. Have you tested the Capacitor and water temp ?
Sorry, just saw this comment. Sometimes the brass /copper pins that make contact in the transmission to the switch need cleaning and that may give you false readings.
I got that sooo many years ago. It was just a terminal depinning kit that I ground down a little. I would recommend getting a terminal test probe kit though. You can find them on eBay or Amazon
Hey Rooster! I just bought a 2016 KX250f that will not start cold. Only way to start it is with a bump start, it will start fine hot. After watching a few of your awesome videos I got a leak down tester and making sure it’s perfectly at TDC with a long arm ratchet on it I hear hear air coming out the air box. Intake seems to be .004 and exhaust seems to be .006. Is it time to take the head off?
Make sure that the engine isn’t moving off of tdc when pressuring the cylinder otherwise it could open the valve slightly. If it’s all good and you are still getting air in the air box or exhaust, the valve is not sealing properly and the head would need to come off. Your clearances are a tick on the right side, I would shim them on the upper side of the range.
Love the diagnostic checks with ohm spec's. I'm dealing with a hard start 2011 KX450 but only after it is hot. I'll check the stator tomorrow just like you did yours. I shimmed all valves and they are now good (all four were out of spec) Starts up cold fine but then it is a no go after hot at which time I have to turn the idle plunger in all the way (off), kick over until it tries to fire, then back the idle out to original position (usually 45 clicks out) and she starts. Leaning towards fuel issue. It has a new All Balls fuel pump rebuild kit and temp sensor but was wondering if you can give me the ohm spec's on the injector? Or......if you have any other idea's on what may cause this. Thank you.
Reading this instantly has me leaning toward a leaking fuel injector. The spec on the injector should be 11.7-12.3 ohms at 20 c or 68 f. This may be in spec but the injector could be weeping fuel into the cylinder. This tends not to matter at cold start because it likes a richer mixture but when its warmed up, the FI bikes do not like any excess fuel. If you can, warm the bike up as usual, then when it wont start, hold the throttle wide open and try again. This will give it plenty of air and activate the fuel cutoff. It would be a good idea to check your fuel pressure when running and after you shut the engine down. After that, it would be checking all of the sensors, ie inlet air temp and pressure sensors, tps and water temp sensor. Good luck!
@@restoroosterohv Thanks for that info! I will try the WOT method to double check for the leaky injector. That very well could be it. If so, I will update here. 👍
@@restoroosterohv OK. I tried the WOT after hot and it would not start. Injector tested at 12.9 ohms (out of spec), BUT when hot the stator tested at 279 ohms (nearly out of spec) between the green and whi/yel leads and then tested at 250 after and hour of cool down. I assume those two wires are for the pickup coil. All the other yellow wires were fine. Not sure what to throw money at first at this point. Ida's brother? Thanks
@@SwormCycles Even thought the WOT test did not work, it could still be your culprit. Do all tests on sensors at "room" temperature (about 68F) or they may be out of spec. Like I said before, my next test would be a fuel pressure test. The pressure should be in the mid 40s when running and drop when you turn it off but will maintain a reading for quite some time. If your injector is leaking, it will bleed off the pressure fairly quickly. Double check your valve clearances when cold as well.
@@restoroosterohv So one last follow up here. I ended up installing a new fuel injector but that did not solve a thing. Bike was even harder to start. Totally left me scratching my head and ready to throw in the towel. I then decided to do one last thing and that was to pull the shift selector switch and check the contacts. Even though they all looked pretty clean, I lightly sanded them down and reinstalled it. Bike started right back up and also started after being hot. I just don't get it. All symptoms pointed to a fuel delivery issue so why sanding of the gear selector helped is beyond me.
Great video. I have a 2020 kx250f that takes several kicks to get started unless I give it a crack of throttle when starting. Valves, top end, and crank were done last summer and only has about 13 hours on them. Any ideas? I have that same cylinder leak down tester and I can't get it to fit in the head.
If it takes a crack of throttle to start, I wouldn't worry about it too much. There are many things that could cause that and you would have to do a full diagnostic. Check the simple things first like spark plug and make sure the air filter is clean. To use the leak tester, you will need a 10mm adapter. www.amazon.com/gp/product/B00CEX5B1Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Just curious why the adapter is needed as most kits seem to come with the m10 adapter. Looking at the Maddox leak down tester from harbor freight. If I need to buy the adapter I will but just wanted to double check as to why before I grabbed it. Your videos have been very helpful. I just bought a 16 kx250f and it will not start cold but will bump start then start fine hot.
I have a orange light now while I kick start the bike. And no start. Even sitting a while. Put new gas in it. Wondering if the fuel pump is not working. Tell me your suggestions Thank you.
The orange light should light while kicking. Three things are required for an engine to run, compression, fuel and spark. Check the valve clearances which could cause compression loss. Pull the spark plug and check for spark. Lastly, you could spray a bit of starting fluid into the back of the throttle body to see if she will fire. Beyond that, you would need to run a complete diagnostic of each system as outlined in this video.
I have a kx 450f 2016 and it just got the bottom engine rebuilt has around 13 hrs on it now it starts around 4th kick cold with no choke but when you ride it for a little and shut it off it take so many tries to start back up.
Although it would be difficult to accurately diagnose your problem without testing the components, one of my viewers had the exact same problem. Pull the plug for the gear switch and check the resistance against the manual in all gears. That ended up being his problem. Whomever rebuilt the bottom end may have left the brass contact pins out.
Just found your channel and really like your content. I have a 2016 kx450 that has sat for 3 years while I healed from a spinal injury and it won't start. It never had anything but race fuel in it but I still cleaned out fuel tank and installed new plug but nothing. I pulled the plug and I'm getting spark and still won't start. Any advice would be awesome. I'm not sure how close your year is to mine but really need some help. Thanks in advance
There are a few things that I would be concerned with first being the fuel pump. No fuel, no start. A fuel pressure test would be ideal. For now, pull the subframe to access the back of the throttle body. Mix some 90+ octane fuel and 2 cycle oil (4oz per gallon of fuel or 32:1) in a cheap Walmart squirt bottle, like the kind for putting ketchup or something. Open the throttle and give it a shot in the back of the throttle body. Close the throttle and give it a few kicks. If it starts, you will have to chase a fuel delivery issue, ie pump, injector etc. Second, it is possible the the rings could be stuck in the piston from sitting causing low compression. A cylinder leakage test would be the ideal test. A little 2 cycle oil down the cylinder could increase the compression temporarily. Lastly, it could be none of these things and would require a full diagnostic (stator, sensors or wiring). Hope this helps.
@@restoroosterohv awesome I'm going to work on it tonight and tomorrow and get back to you if that's ok. You mentioned mixing gas and squirting it in the throttle body, knowing it's a 4 stroke will that hurt anything or is that ok for my bike? Thanks again
@@stringbender247 Fuel mixed with 2-cycle oil will help lubricate the dry cylinder walls, piston and rings from sitting. It's a must even on your 4 stroke. Let me know how it goes or if you need any more help.
I have a 2013 kx450, it will start fine and idle pretty decent, on the throttle its got great power. but on the mid range with constant throttle it cuts out a little and pops a little on decelleration. I checked the throttle position sensor and I was within spec at (.59v), I also replaced the fuel filter and pump. I was told to run the different maps that it came with, so i switched those 3 around and it had no change. I have noticed after starting it up and it idling if I accidently kill it by over clutching, it will take 4-8 kicks until it runs again. After this video I am definitely going to be checking out the coolant temp sensor. Do you have any thoughts?
Decel pops are telling you it’s lean. Did you replace the pump only or the entire module? There are two O-rings in there that are critical, and your fuel pressure regulator could potentially be bad. I would look for air leaks around the intake boot. Check the hose from the throttle body to the MAP sensor to be sure it’s not cracked or fell off. I would also do a fuel pressure check. Exhaust leaks can also cause deceleration pops, but generally won’t cause starting issues.
@@restoroosterohv I just replaced the the pump and the filter, not the whole unit. I didnt touch any o-rings, but none of them looked that bad. Which O-rings are you referring to? I'll pressure test it tonight, what pressure should I be looking for?
@bradleyhille6163 check out my video on a Kawasaki KFX450R (Episode 68). The pump assemblies are very similar and I go into depth. 43 PSI is where you want to be. Also, when the bike is shut down, it should hold pressure for a bit and not drop to zero immediately. You can use a 12v battery in place of the capacitor to power the pump or power the pump directly, that makes it easier.
Great Video...! Thanks a lot for your help to another person... I raed all comments and answers. I have problems with my KLX 250S '09 with EFI...good condition 13kkm ODO, no mod... bought 1 month ago. bike start enough easy when is cold, but will not (re-)start (without throttle) when is hot, but with some throttle will start always. In addition when engine is warm and I give a fast throttle it can often die. Good fuel is in tank, battery is OK (10,5+V when starting), I changed spark plug (old in good condition and colours), air cleaner OK, I checked mainTPS input and output Voltage (in specs), I checked water temperature sensor (i think is OK). I don't know a valve clearance... I'll check it in near future. What can I check to resolve...? Great THANKS for any comments. PS I found 2 or 3 topics with the same symptoms in KLX in the internet, but no one ends resolving. 😥
Thanks for your feedback and support. Unfortunately with an EFI bike, there are many factors. While I wouldn't rule it out completely, I don't think valve lash would be your culprit. I would be 100% sure that your water (and IAT if applicable) sensors are providing the correct readings both when cold and hot. My next check would be a fuel pressure test to be sure that the pressure is in spec (40-45 psi, check hot and cold) and to also be sure that the regulator or injector are not bleeding down the pressure quickly after the engine is stopped. A leaking fuel injector can cause excess fuel in the cylinder that can sometimes be cleared by holding the throttle open slightly to allow more air in. EFI bikes generally don't like any throttle to be applied while trying to start. There are some reports of issues arising from a mis-adjusted decompression mechanism but honestly I have no experience with that. Good luck and keep me posted.
@@restoroosterohv Thank You for very fast and helpful answer. I checked the sensors: water temperature, and inlet air temperature. Both of them are in 99% OK... i measured a resistance in every temperature as watch in service manual (without -20°C ;)) ). Only water temperature sensor has probably (my precision of measure) too low resistance in 40°C (a little too low). I bought a new water temperature sensor for peace of mind. And next what I'll check is fuel pressure... ...and I'll let you know how it looks. Best regards!
@@przemysawszemraj2040 You'd probably be looking for an extremely out of spec sensor at operating temperature (around 90C) but it doesn't sound like that is the case.
@@restoroosterohv Hello, I'm here again... what's new: I checked fuel pressure... it's OK (40 PSI - with my pressure gauge... and unknown accuracy) I make a video of my case... please watch if you can (pressure measurement and another symptoms). czcams.com/video/IqaWpd8-B9U/video.html Best regards!
Hi, after some months I'm back... in those time I checked the clearance, and are in specs... But I have new fact: czcams.com/video/RbKCe_EZE7A/video.html Please look at that... It was a last test... jump cables...!!! and YES! 😮 on cables warm engine started well.. I have buy a new battery, but it didn't help. I don't know what does it mean... Starter? High voltage wire? Another wire's? Please help! Thanks a lot!
I have a Kx250F 2015 its really hard to start and when finally start it bogg when i put throttle on her for like 1 second and then not bogg, I tried changing the spark plug and now i’m going to change the gas filter that its dirty. Any other recommendation?
Check the plug 1st thing. I rebuilt the fuel pump, replaced the water coolant sensor and after all that it was a burnt up plug. Completely black when I took it out. The plug fixed everything.
The cause of the hard starting is addressed in the video. Obviously checking the easy stuff first would be your best bet. I would be concerned why your plug was fouled in the first place, you may have underlying issues.
@restoroosterohv9030 I obviously know the issue and finding the issue was the entire point of the video. I was only sharing my recent experience and my point was I SHOULD HAVE CHECKED THE PLUG FIRST! Thanks for your confirmation.
@restoroosterohv9030 and yes, the fuel pump had a torn o ring that may have been the issue with the plug. Before all of this I had a new crank put in because of hours on it, and the valves adjusted.
@@anthonyschenck7076 when the power point in your car stops working, the first thing you check is the fuse before ripping all the wiring apart so absolutely check the obvious and easy stuffs first. I'm curious, have you pulled the plug and rechecked it to see if it is still fuel fouling since fixing the o-ring? I believe those pump assemblies have a pressure regulator built in and a leak in an o-ring would maybe cause a lean condition?
@restoroosterohv9030 the plug was solid black last time. In 2nd gear, when I'm zooming along at high rpms, after a couple hours of riding, my bike backfires or spits fire on occasion. It mainly only does it in 2nd gear. Does that mean anything?
I seen the comments and i likeit that u answer always trying to help them. I need some help because i have a kx2007f i and dont know what happens. Is too difficult sometimes start the bike, like 30 kick.. but in another try's, she starts in 1-3 kicks. I change with a new spark plug, clean air filter, new oil and oil filter, checks the wire, testing with carburator air reguler. The bike once start, works good.. sometimes a little bit of blue smoke when i accelerate but bit.. i hope u can helpme in something, thanks!
im looking the full video and i suspect about of coolant temperature sensor and i going to check in my bike and i question to my brother about this connection and he says that is not pluged in any part, thats be a problem or if not connected doenst matter?
@@restoroosterohvi think the first owner he puts one,or trying.I can contact with you for gmail or something and i share photos?Thank u so much for reply
The first thing you should check is your valve clearances. My very first video shows how to check these here czcams.com/video/osFLZ0HTP5E/video.htmlsi=rhpdYZouI1-yJBfI If the clearances are tight, it will be hard to kick start. If I am understanding you correctly, you have a 2007 KX. This is not a fuel injected bike and will not have a temp sensor. Most likely causes are valve clearances, low compression or carburetor adjustments.
What was the final problem with this bike? I’m chasing a no start on my 2012 kx250. Changed the fuel pump and filter (the bike sat for a while) plus the plug. New gas. Still won’t start
This bike ended up being a damaged coolant temp sensor. Does it have spark? If so, my next steps would be to do a fuel pressure check, and a cylinder leakage test
@@restoroosterohv I’ll try that next. It ran great then it sat for about a year and a half. Just lost interest in riding. But now I’m wanting to get back into it and having to go through the pain of it not starting. It does have spark. I changed the plug anyways.
@pingpong4016 did you put a complete pump module or just an aftermarket pump? You will need to see 43 psi fuel pressure with 12v connected to the condenser plug. It should maintain that pressure for a good while after power is disconnected. The cylinder leakage test will let you know that the valves, rings and head gasket are sealing properly.
@@restoroosterohv just the pump and filter itself. Kept the same housing/module. I’ll check compression and fuel pressure. Then come back with results. It acts like it doesn’t even want to start.
My crank sensor is reading ZERO AND my stator resistance is reading 0.03 yesterday and 0.0 today. Both grounds are infinite ♾️. I need a stator right? My bike was starting and riding good but 3rd gear max max made it surge buck pop and I have to slow down to let it calm down. I have ordered a fuel pump fuel hose injector capacitor stator coolant temp sensor. My hour meter is working so I’m guessing my coil works?
@@restoroosterohv I’ve checked it 2 days in a row. Last days riding my bike was very very hot to the touch so I think I’ve reached it’s peak everything is reading mighty low but if I check my other bike battery and things it reads normal levels so I think I put about 350 hours on this bike so it’s time to replace a lot of stuff or maybe just stator and watch it charge up the rest of the system
Great Vid my guy👍 Could you help me i have same bike, but my rear fuel injector is leaking a small amount while idle causing leaking out my airbox boot dripping down my throttle body I pressure cleaned the injector im wondering if my TPS would cause this problem?? Thanks in advance!!!
Great name! Ive never encountered that issue. You would need to ohm out the TPS and compare it to the specs in the manual. If the injector is constantly leaking fuel, it would need to be replaced. It may have some debris inside of it causing it not to fully close. Normally in a case like that, the bike would run very poorly due to the excessively rich condition. Are you sure it is not oil?
Positive, I had a guy take the throttle body off to clean and he removed the TPS unknown to it needing to be adjusted to certain ohm’s anytime being removed out such. It originally was an idle problem after putting it back together though is when it was leaking the access fuel!! I watched inside the throttle body as i gave it gas the injector opens, but at idle it still has a heavy drip causing it to flood itself… I REALLY APPRECIATE THE FEEDBACK!!!!
Hi. Quisiera hacer una consulta si es tan amable por favor. Resulta que fui a ver una kx450f 2015 se veia bien y sonaba bien,pero a la hora de provarla en la calle se siente muy lenta y sin power lo cual me sorprendio. Alguna idea de lo que podria ser? Thanks
Hay demasiadas razones para esto, desde la presión del combustible hasta la baja compresión y problemas con los sensores. Yo comenzaría haciendo una prueba de compresión y una prueba de fuga del cilindro para ver cuál es el estado del motor.
@@restoroosterohv ok entiendo voy a tomar en cuenta lo que usted me sugiere tambien pense en que quizas este fuera de tiempo, pero comenzare con su sugerencia. Gracias hermano
Recently got a 2012 kx450f runs great throttle response is good cranks up on first or 2nd kick but every so often if I’m going fast it will start to bog down and shut off,but cranks right back up after. If anyone has tips please help
It should be between 1430-1580 ohms. Pull the sensor off and test it on the bench. If it is still way off, replace the sensor. If it’s good, clean all the contacts with 0000 steel wool or a scotch brite and reinstall/retest.
What are the symptoms of a bad gear shift sensor? I have a rmz450 20016 that sputters under load, sometimes shuts off under power. And seems to be running rich and lacking power. Yet other times, seems to run ok. It seems heat related. At one point the idle adjustment seemed to make no difference. I replaced the coolant temp sensor and the stator and fuel pump. Valve clearance was check twice. I have no idea at this point. This bike totally pisses me off
The gear shift sensor can definitely cause running issues. I would certainly invest some time in checking the ohm specs on the shift position sensor, IAT sensor and TPS just to be sure. Another test I personally would run is a fuel pressure test. At idle and under load. They can be frustrating but there is a cause so eliminate the possibilities one by one.
@@restoroosterohv I did a pressure test on the fuel pump, but replaced it once with an oem, then another. It's definitely not that. I need this bike fix for Orlando Christmas race. Where are you located? Do you know of any recalls for this? I heard tps?
I’m having a issue I was riding the bike pretty hard and it started to bogg and died after that it was hard to start and when it did start it wouldn’t idle and would just die
What year? I would check your valve clearances first off. Try throwing a new spark plug in it. Otherwise you will need to do a component to component diagnostic similar to what I did in this video.
@@Blocanbentlyyahu there are many potential causes including valves, compression, fuel delivery, ignition system to any of the sensors. A step by step diagnostic will need to be performed.
Not following through the bottom of your kick. Start standing and sit as you kick it all the way down. Use your body weight to follow through all the way down. One strong kick every time no fast light kicks at the top like a two stroke. I can almost guarantee this will make it start right away. That’s why everything looks fine when you tore it down.
I never tore this bike down. This bike is a FI bike. Normal starting procedure is a few fast kicks to “charge” the capacitor and build fuel pressure. Then a strong TDC kick or two generally will start them. This particular bike had an issue with the coolant temp sensor. Started and ran as it should when remedied and is now my personal bike.
There were a lot of kicks because there was an issue with the DFI system and not procedure. She is a reliable beast now. Thanks for your comments and ride safe!
From going from a 2000 kx250 , to a 2023 kx450x, wow what a huge change in performance and technology. Got bike home and completely tore it down to just engine in chassis, lubed and greased everything and retorquorted everything to spec . But watching your videos on the multiple sensors and ohms check really gives me a peace of mind! Thanks alot for your info
Thank you for your feedback and support. You’re certainly not the kind of guy I buy my bikes from (they don’t even change the oil). Good luck with your new bike and ride safe.
I now understand your channel and what you do , I'm very impressed and i love to learn something new everyday. I've probably watched now 8 or 10 of your videos today . Always something new to learn from you. I'm a tincker , my wife about shit herself, when she opened the garage door up yesterday and saw a new kx450x in a hundred pieces. Lol i blamed you.
I appreciate your feedback and support. Don’t let me down, make sure you get that baby back together correctly!
I have a 2014 kx250f with the same exact issue. This video will help with my diagnosis.
I sure hope it does
I’m learning a ton watching these. The AMA should hire you as a part time mechanic. I actually know a guy if you’re interested?
Thank you for your feedback and support. I appreciate your offer too.
Awesome fideo 👍
Appreciate your feedback and support.
I have a 14 kx450 also and I replaced the fuel pump filter and it ran fine but I rode it for about 20 mins and shut it off and then it wouldn’t start again. The only way I can get it to start now is if I hook up a 12v battery to the capacitor connector or kick it like 50 times. I replaced the capacitor but that didn’t do anything and the stator is .1 over spec and the ignition coil is .5 over spec for the primary and secondary is in spec. The valves were adjusted about 5 hours ago
Have you checked ALL three stator coils across each other and to ground? If all of those coils check out ok, I would do a fuel pressure check. I wouldn't worry about the coil because it runs. Sounds like a fuel pressure issue either due to a leak or bypass in the pump module/regulator or the stator is not providing enough power to run the pump during kicking.
Thanks I’ll check those out
I got a 16 kx 450 bike was running super lean and backfiring not really hard to start but I did valve adjustment and new fuel filter and now the bike doesn’t want to start at all valves are all in spec and timings spot on
If you’re 100% sure that the timing is correct, and the valve clearances are correct, pull the fuel line off of the tank, hook a piece of rubber hose to the pump and into a bucket. Give it a few kicks to see what kind of fuel flow you have. Ideally, you would want to do a fuel pressure test. I have a newer video out on replacing the timing chain and it goes over the timing marks if you’d like to look at that as a back up.
@@restoroosterohv timing was off haha but I’m getting black smoke coming out of the pipe any ideas on that?
@@nickmee3321 black smoke is representative of a rich condition, blue would be oil burning and white is condensation or water burning. Is it showing black smoke in all riding conditions or just when on the throttle?
@@restoroosterohv haven't ridden it yet its just a little smoke when you rev it up also dose backfire a little
@@nickmee3321 Double check your timing again. It should not be backfiring.
Great video. Front forks look like they're off a way older model
Wow, you have a good eye. Someone had swapped out the air fork for 98 KX250 forks. I have since replaced them with later model forks but still sprung.
My 2007 kx450 also has the same. Why would somone swop the forks
On the newer bikes, sometimes people don’t want the air forks so they will use spring forks from another bike. I certainly can’t speculate why someone changed the forks on your 07.
Wow thanks my my gear position sensor is bad the actual first sensor I’ve seen go bad through my own testing. Have you tested the Capacitor and water temp ?
Sorry, just saw this comment. Sometimes the brass /copper pins that make contact in the transmission to the switch need cleaning and that may give you false readings.
Have a link for the pin tools you used with your multi meter? Thanks!
I got that sooo many years ago. It was just a terminal depinning kit that I ground down a little. I would recommend getting a terminal test probe kit though. You can find them on eBay or Amazon
Hey Rooster! I just bought a 2016 KX250f that will not start cold. Only way to start it is with a bump start, it will start fine hot. After watching a few of your awesome videos I got a leak down tester and making sure it’s perfectly at TDC with a long arm ratchet on it I hear hear air coming out the air box. Intake seems to be .004 and exhaust seems to be .006. Is it time to take the head off?
Make sure that the engine isn’t moving off of tdc when pressuring the cylinder otherwise it could open the valve slightly. If it’s all good and you are still getting air in the air box or exhaust, the valve is not sealing properly and the head would need to come off. Your clearances are a tick on the right side, I would shim them on the upper side of the range.
Love the diagnostic checks with ohm spec's. I'm dealing with a hard start 2011 KX450 but only after it is hot. I'll check the stator tomorrow just like you did yours. I shimmed all valves and they are now good (all four were out of spec) Starts up cold fine but then it is a no go after hot at which time I have to turn the idle plunger in all the way (off), kick over until it tries to fire, then back the idle out to original position (usually 45 clicks out) and she starts. Leaning towards fuel issue. It has a new All Balls fuel pump rebuild kit and temp sensor but was wondering if you can give me the ohm spec's on the injector? Or......if you have any other idea's on what may cause this. Thank you.
Reading this instantly has me leaning toward a leaking fuel injector. The spec on the injector should be 11.7-12.3 ohms at 20 c or 68 f. This may be in spec but the injector could be weeping fuel into the cylinder. This tends not to matter at cold start because it likes a richer mixture but when its warmed up, the FI bikes do not like any excess fuel. If you can, warm the bike up as usual, then when it wont start, hold the throttle wide open and try again. This will give it plenty of air and activate the fuel cutoff. It would be a good idea to check your fuel pressure when running and after you shut the engine down. After that, it would be checking all of the sensors, ie inlet air temp and pressure sensors, tps and water temp sensor. Good luck!
@@restoroosterohv Thanks for that info! I will try the WOT method to double check for the leaky injector. That very well could be it. If so, I will update here. 👍
@@restoroosterohv OK. I tried the WOT after hot and it would not start. Injector tested at 12.9 ohms (out of spec), BUT when hot the stator tested at 279 ohms (nearly out of spec) between the green and whi/yel leads and then tested at 250 after and hour of cool down. I assume those two wires are for the pickup coil. All the other yellow wires were fine. Not sure what to throw money at first at this point. Ida's brother? Thanks
@@SwormCycles Even thought the WOT test did not work, it could still be your culprit. Do all tests on sensors at "room" temperature (about 68F) or they may be out of spec. Like I said before, my next test would be a fuel pressure test. The pressure should be in the mid 40s when running and drop when you turn it off but will maintain a reading for quite some time. If your injector is leaking, it will bleed off the pressure fairly quickly. Double check your valve clearances when cold as well.
@@restoroosterohv So one last follow up here. I ended up installing a new fuel injector but that did not solve a thing. Bike was even harder to start. Totally left me scratching my head and ready to throw in the towel. I then decided to do one last thing and that was to pull the shift selector switch and check the contacts. Even though they all looked pretty clean, I lightly sanded them down and reinstalled it. Bike started right back up and also started after being hot. I just don't get it. All symptoms pointed to a fuel delivery issue so why sanding of the gear selector helped is beyond me.
Great video. I have a 2020 kx250f that takes several kicks to get started unless I give it a crack of throttle when starting. Valves, top end, and crank were done last summer and only has about 13 hours on them. Any ideas? I have that same cylinder leak down tester and I can't get it to fit in the head.
If it takes a crack of throttle to start, I wouldn't worry about it too much. There are many things that could cause that and you would have to do a full diagnostic. Check the simple things first like spark plug and make sure the air filter is clean. To use the leak tester, you will need a 10mm adapter.
www.amazon.com/gp/product/B00CEX5B1Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Just curious why the adapter is needed as most kits seem to come with the m10 adapter. Looking at the Maddox leak down tester from harbor freight. If I need to buy the adapter I will but just wanted to double check as to why before I grabbed it. Your videos have been very helpful. I just bought a 16 kx250f and it will not start cold but will bump start then start fine hot.
@dragin79 my kit did not come with that adapter. Check your valve clearances for cold start difficulties.
I have a orange light now while I kick start the bike. And no start. Even sitting a while. Put new gas in it. Wondering if the fuel pump is not working. Tell me your suggestions
Thank you.
The orange light should light while kicking. Three things are required for an engine to run, compression, fuel and spark. Check the valve clearances which could cause compression loss. Pull the spark plug and check for spark. Lastly, you could spray a bit of starting fluid into the back of the throttle body to see if she will fire. Beyond that, you would need to run a complete diagnostic of each system as outlined in this video.
I have a kx 450f 2016 and it just got the bottom engine rebuilt has around 13 hrs on it now it starts around 4th kick cold with no choke but when you ride it for a little and shut it off it take so many tries to start back up.
Although it would be difficult to accurately diagnose your problem without testing the components, one of my viewers had the exact same problem. Pull the plug for the gear switch and check the resistance against the manual in all gears. That ended up being his problem. Whomever rebuilt the bottom end may have left the brass contact pins out.
Just found your channel and really like your content. I have a 2016 kx450 that has sat for 3 years while I healed from a spinal injury and it won't start. It never had anything but race fuel in it but I still cleaned out fuel tank and installed new plug but nothing. I pulled the plug and I'm getting spark and still won't start. Any advice would be awesome. I'm not sure how close your year is to mine but really need some help. Thanks in advance
There are a few things that I would be concerned with first being the fuel pump. No fuel, no start. A fuel pressure test would be ideal. For now, pull the subframe to access the back of the throttle body. Mix some 90+ octane fuel and 2 cycle oil (4oz per gallon of fuel or 32:1) in a cheap Walmart squirt bottle, like the kind for putting ketchup or something. Open the throttle and give it a shot in the back of the throttle body. Close the throttle and give it a few kicks. If it starts, you will have to chase a fuel delivery issue, ie pump, injector etc. Second, it is possible the the rings could be stuck in the piston from sitting causing low compression. A cylinder leakage test would be the ideal test. A little 2 cycle oil down the cylinder could increase the compression temporarily. Lastly, it could be none of these things and would require a full diagnostic (stator, sensors or wiring). Hope this helps.
@@restoroosterohv awesome I'm going to work on it tonight and tomorrow and get back to you if that's ok. You mentioned mixing gas and squirting it in the throttle body, knowing it's a 4 stroke will that hurt anything or is that ok for my bike? Thanks again
@@stringbender247 Fuel mixed with 2-cycle oil will help lubricate the dry cylinder walls, piston and rings from sitting. It's a must even on your 4 stroke. Let me know how it goes or if you need any more help.
@@restoroosterohv oh ok I'm tracking just wanted to double check. Man I can't thank you enough.
@@stringbender247 You're welcome
I have a 2013 kx450, it will start fine and idle pretty decent, on the throttle its got great power. but on the mid range with constant throttle it cuts out a little and pops a little on decelleration. I checked the throttle position sensor and I was within spec at (.59v), I also replaced the fuel filter and pump. I was told to run the different maps that it came with, so i switched those 3 around and it had no change. I have noticed after starting it up and it idling if I accidently kill it by over clutching, it will take 4-8 kicks until it runs again. After this video I am definitely going to be checking out the coolant temp sensor.
Do you have any thoughts?
Decel pops are telling you it’s lean. Did you replace the pump only or the entire module? There are two O-rings in there that are critical, and your fuel pressure regulator could potentially be bad. I would look for air leaks around the intake boot. Check the hose from the throttle body to the MAP sensor to be sure it’s not cracked or fell off. I would also do a fuel pressure check. Exhaust leaks can also cause deceleration pops, but generally won’t cause starting issues.
@@restoroosterohv I just replaced the the pump and the filter, not the whole unit. I didnt touch any o-rings, but none of them looked that bad. Which O-rings are you referring to? I'll pressure test it tonight, what pressure should I be looking for?
@bradleyhille6163 check out my video on a Kawasaki KFX450R (Episode 68). The pump assemblies are very similar and I go into depth. 43 PSI is where you want to be. Also, when the bike is shut down, it should hold pressure for a bit and not drop to zero immediately. You can use a 12v battery in place of the capacitor to power the pump or power the pump directly, that makes it easier.
Sweet, thank you for the help!
@@restoroosterohv
fuel pump issue?
nice
Thanks
Great Video...! Thanks a lot for your help to another person... I raed all comments and answers.
I have problems with my KLX 250S '09 with EFI...good condition 13kkm ODO, no mod... bought 1 month ago.
bike start enough easy when is cold, but will not (re-)start (without throttle) when is hot, but with some throttle will start always.
In addition when engine is warm and I give a fast throttle it can often die.
Good fuel is in tank, battery is OK (10,5+V when starting), I changed spark plug (old in good condition and colours), air cleaner OK, I checked mainTPS input and output Voltage (in specs), I checked water temperature sensor (i think is OK).
I don't know a valve clearance... I'll check it in near future.
What can I check to resolve...?
Great THANKS for any comments.
PS
I found 2 or 3 topics with the same symptoms in KLX in the internet, but no one ends resolving. 😥
Thanks for your feedback and support. Unfortunately with an EFI bike, there are many factors. While I wouldn't rule it out completely, I don't think valve lash would be your culprit. I would be 100% sure that your water (and IAT if applicable) sensors are providing the correct readings both when cold and hot. My next check would be a fuel pressure test to be sure that the pressure is in spec (40-45 psi, check hot and cold) and to also be sure that the regulator or injector are not bleeding down the pressure quickly after the engine is stopped. A leaking fuel injector can cause excess fuel in the cylinder that can sometimes be cleared by holding the throttle open slightly to allow more air in. EFI bikes generally don't like any throttle to be applied while trying to start. There are some reports of issues arising from a mis-adjusted decompression mechanism but honestly I have no experience with that. Good luck and keep me posted.
@@restoroosterohv Thank You for very fast and helpful answer.
I checked the sensors: water temperature, and inlet air temperature. Both of them are in 99% OK... i measured a resistance in every temperature as watch in service manual (without -20°C ;)) ). Only water temperature sensor has probably (my precision of measure) too low resistance in 40°C (a little too low).
I bought a new water temperature sensor for peace of mind.
And next what I'll check is fuel pressure...
...and I'll let you know how it looks.
Best regards!
@@przemysawszemraj2040 You'd probably be looking for an extremely out of spec sensor at operating temperature (around 90C) but it doesn't sound like that is the case.
@@restoroosterohv Hello, I'm here again... what's new:
I checked fuel pressure... it's OK (40 PSI - with my pressure gauge... and unknown accuracy)
I make a video of my case... please watch if you can (pressure measurement and another symptoms).
czcams.com/video/IqaWpd8-B9U/video.html
Best regards!
Hi, after some months I'm back... in those time I checked the clearance, and are in specs...
But I have new fact: czcams.com/video/RbKCe_EZE7A/video.html
Please look at that...
It was a last test... jump cables...!!! and YES! 😮 on cables warm engine started well..
I have buy a new battery, but it didn't help.
I don't know what does it mean...
Starter?
High voltage wire?
Another wire's?
Please help!
Thanks a lot!
Good stuff man 🤙🏾
Are the specs the same on the 2010? Save me a google search?
Peetty much same symptoms only mine is hard to keep idle once started gatta keep revving it, but it tuns awesome once started
Not all specs are the same. I would recommend a service manual for your repairs.
I have a Kx250F 2015 its really hard to start and when finally start it bogg when i put throttle on her for like 1 second and then not bogg, I tried changing the spark plug and now i’m going to change the gas filter that its dirty. Any other recommendation?
I recommend a fuel pressure check. Is your FI light on?
Check the plug 1st thing. I rebuilt the fuel pump, replaced the water coolant sensor and after all that it was a burnt up plug. Completely black when I took it out. The plug fixed everything.
The cause of the hard starting is addressed in the video. Obviously checking the easy stuff first would be your best bet. I would be concerned why your plug was fouled in the first place, you may have underlying issues.
@restoroosterohv9030 I obviously know the issue and finding the issue was the entire point of the video. I was only sharing my recent experience and my point was I SHOULD HAVE CHECKED THE PLUG FIRST! Thanks for your confirmation.
@restoroosterohv9030 and yes, the fuel pump had a torn o ring that may have been the issue with the plug. Before all of this I had a new crank put in because of hours on it, and the valves adjusted.
@@anthonyschenck7076 when the power point in your car stops working, the first thing you check is the fuse before ripping all the wiring apart so absolutely check the obvious and easy stuffs first. I'm curious, have you pulled the plug and rechecked it to see if it is still fuel fouling since fixing the o-ring? I believe those pump assemblies have a pressure regulator built in and a leak in an o-ring would maybe cause a lean condition?
@restoroosterohv9030 the plug was solid black last time. In 2nd gear, when I'm zooming along at high rpms, after a couple hours of riding, my bike backfires or spits fire on occasion. It mainly only does it in 2nd gear. Does that mean anything?
My kxf 250 2018, while driving 5. Speed and 1-2 seconds suffocates. like the ignition goes out, what could it be?
I would do a fuel pressure test to start.
@@restoroosterohv Do you need to know 3 bars at 12 volts?
Yes, that is perfect.
I seen the comments and i likeit that u answer always trying to help them. I need some help because i have a kx2007f i and dont know what happens. Is too difficult sometimes start the bike, like 30 kick.. but in another try's, she starts in 1-3 kicks. I change with a new spark plug, clean air filter, new oil and oil filter, checks the wire, testing with carburator air reguler. The bike once start, works good.. sometimes a little bit of blue smoke when i accelerate but bit.. i hope u can helpme in something, thanks!
im looking the full video and i suspect about of coolant temperature sensor and i going to check in my bike and i question to my brother about this connection and he says that is not pluged in any part, thats be a problem or if not connected doenst matter?
The 2007 will not have a coolant temperature sensor.
@@restoroosterohvi think the first owner he puts one,or trying.I can contact with you for gmail or something and i share photos?Thank u so much for reply
The first thing you should check is your valve clearances. My very first video shows how to check these here czcams.com/video/osFLZ0HTP5E/video.htmlsi=rhpdYZouI1-yJBfI
If the clearances are tight, it will be hard to kick start. If I am understanding you correctly, you have a 2007 KX. This is not a fuel injected bike and will not have a temp sensor. Most likely causes are valve clearances, low compression or carburetor adjustments.
What was the final problem with this bike? I’m chasing a no start on my 2012 kx250. Changed the fuel pump and filter (the bike sat for a while) plus the plug. New gas. Still won’t start
This bike ended up being a damaged coolant temp sensor. Does it have spark? If so, my next steps would be to do a fuel pressure check, and a cylinder leakage test
@@restoroosterohv I’ll try that next. It ran great then it sat for about a year and a half. Just lost interest in riding. But now I’m wanting to get back into it and having to go through the pain of it not starting. It does have spark. I changed the plug anyways.
@pingpong4016 did you put a complete pump module or just an aftermarket pump? You will need to see 43 psi fuel pressure with 12v connected to the condenser plug. It should maintain that pressure for a good while after power is disconnected. The cylinder leakage test will let you know that the valves, rings and head gasket are sealing properly.
@@restoroosterohv just the pump and filter itself. Kept the same housing/module. I’ll check compression and fuel pressure. Then come back with results. It acts like it doesn’t even want to start.
@pingpong4016 if the pressure regulator or orings in that module are bad, you won’t have fuel pressure and a no start. Let me know.
My crank sensor is reading ZERO AND my stator resistance is reading 0.03 yesterday and 0.0 today. Both grounds are infinite ♾️. I need a stator right? My bike was starting and riding good but 3rd gear max max made it surge buck pop and I have to slow down to let it calm down. I have ordered a fuel pump fuel hose injector capacitor stator coolant temp sensor. My hour meter is working so I’m guessing my coil works?
The bike wouldn’t run if the crank sensor was zero. Sounds like you need a tester that is a little more accurate.
@@restoroosterohv yeah it’s not cranking anymore
@@restoroosterohv I’ve checked it 2 days in a row. Last days riding my bike was very very hot to the touch so I think I’ve reached it’s peak everything is reading mighty low but if I check my other bike battery and things it reads normal levels so I think I put about 350 hours on this bike so it’s time to replace a lot of stuff or maybe just stator and watch it charge up the rest of the system
Stators fail, it’s not uncommon.
Great Vid my guy👍 Could you help me i have same bike, but my rear fuel injector is leaking a small amount while idle causing leaking out my airbox boot dripping down my throttle body I pressure cleaned the injector im wondering if my TPS would cause this problem?? Thanks in advance!!!
Great name! Ive never encountered that issue. You would need to ohm out the TPS and compare it to the specs in the manual. If the injector is constantly leaking fuel, it would need to be replaced. It may have some debris inside of it causing it not to fully close. Normally in a case like that, the bike would run very poorly due to the excessively rich condition. Are you sure it is not oil?
Positive, I had a guy take the throttle body off to clean and he removed the TPS unknown to it needing to be adjusted to certain ohm’s anytime being removed out such. It originally was an idle problem after putting it back together though is when it was leaking the access fuel!! I watched inside the throttle body as i gave it gas the injector opens, but at idle it still has a heavy drip causing it to flood itself…
I REALLY APPRECIATE THE FEEDBACK!!!!
@@justincase5400 May have to get a running fuel pressure measurement to be sure you are at 43 psi (ish). More than likely you have a faulty injector
Thanks man i really do appreciate you more than a lot!!!
@justincase5400 thank you for watching and for your support.
Hi. Quisiera hacer una consulta si es tan amable por favor. Resulta que fui a ver una kx450f 2015 se veia bien y sonaba bien,pero a la hora de provarla en la calle se siente muy lenta y sin power lo cual me sorprendio. Alguna idea de lo que podria ser? Thanks
Hay demasiadas razones para esto, desde la presión del combustible hasta la baja compresión y problemas con los sensores. Yo comenzaría haciendo una prueba de compresión y una prueba de fuga del cilindro para ver cuál es el estado del motor.
@@restoroosterohv ok entiendo voy a tomar en cuenta lo que usted me sugiere tambien pense en que quizas este fuera de tiempo, pero comenzare con su sugerencia. Gracias hermano
Recently got a 2012 kx450f runs great throttle response is good cranks up on first or 2nd kick but every so often if I’m going fast it will start to bog down and shut off,but cranks right back up after. If anyone has tips please help
That’s a tough one. Could potentially be a fuel pump going out.
what if I have 9.16 ohms in neutral, the rest of the gears are ok
It should be between 1430-1580 ohms. Pull the sensor off and test it on the bench. If it is still way off, replace the sensor. If it’s good, clean all the contacts with 0000 steel wool or a scotch brite and reinstall/retest.
@@restoroosterohv does this sensor work in oil? because when I unscrew the cover, there is oil
@endurowarioty yes. It is sealed and the reason for the oring around the perimeter.
What are the symptoms of a bad gear shift sensor?
I have a rmz450 20016 that sputters under load, sometimes shuts off under power. And seems to be running rich and lacking power. Yet other times, seems to run ok. It seems heat related. At one point the idle adjustment seemed to make no difference. I replaced the coolant temp sensor and the stator and fuel pump. Valve clearance was check twice. I have no idea at this point. This bike totally pisses me off
The gear shift sensor can definitely cause running issues. I would certainly invest some time in checking the ohm specs on the shift position sensor, IAT sensor and TPS just to be sure. Another test I personally would run is a fuel pressure test. At idle and under load. They can be frustrating but there is a cause so eliminate the possibilities one by one.
@@restoroosterohv I did a pressure test on the fuel pump, but replaced it once with an oem, then another. It's definitely not that. I need this bike fix for Orlando Christmas race. Where are you located? Do you know of any recalls for this? I heard tps?
What was the fuel pressure? I am in north Georgia.
@@restoroosterohv 43 psi
@@restoroosterohv I believe it's an electrical issue. I have replaced the stator, coolant temp sensor, spark plug. Flywheel looked fine
I’m having a issue I was riding the bike pretty hard and it started to bogg and died after that it was hard to start and when it did start it wouldn’t idle and would just die
What year? I would check your valve clearances first off. Try throwing a new spark plug in it. Otherwise you will need to do a component to component diagnostic similar to what I did in this video.
@@restoroosterohv it’s a 2016 kx450f but I haven’t tested those. But my bike was starting first kick prior to that so would it be my valves ?
@@Blocanbentlyyahu there are many potential causes including valves, compression, fuel delivery, ignition system to any of the sensors. A step by step diagnostic will need to be performed.
Not following through the bottom of your kick. Start standing and sit as you kick it all the way down. Use your body weight to follow through all the way down. One strong kick every time no fast light kicks at the top like a two stroke. I can almost guarantee this will make it start right away. That’s why everything looks fine when you tore it down.
I never tore this bike down. This bike is a FI bike. Normal starting procedure is a few fast kicks to “charge” the capacitor and build fuel pressure. Then a strong TDC kick or two generally will start them. This particular bike had an issue with the coolant temp sensor. Started and ran as it should when remedied and is now my personal bike.
I see. I have a 2015 it always starts within 3 kicks following how I described above. All those kicks will tire u out quick.
There were a lot of kicks because there was an issue with the DFI system and not procedure. She is a reliable beast now. Thanks for your comments and ride safe!