Why dirt bike engines blow up and how to prevent it!
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- čas přidán 11. 06. 2024
- Hey guys today we have something special for you guys, we met with very experienced engine builder Brad from @parapros and talked about the main reasons why dirt bike engines blow up and how to prevent it. Check out the video and let me know your thoughts, cheers!
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why dirt bike engine blow up, explodes, seize - Auta a dopravní prostředky
Warm them up, use good, fresh fuel, change the oil & oil filter often and keep the air filter clean. Other than that, just follow the manual for valve tolerances and change the piston & rings when you should. Remember, an hour meter is your friend!
Just for your information, 87 octane in usa even to 92 octane in Europe. Premium 93 = 98 European
Usa just just use different measurement methods
Yes, in Europe we use RON (research octane number) and in USA they use MON (motor octane number). I run my bikes with 98E5 ethanol 5% and 98 RON.
Good video. I would like to add the eight reason for motor failure. Too hard reving with too cold motor. Piston will seize in the cylinder as it expands too fast and cylinder does not have time to expand so fast so the piston to cylinder clearance gets too tight.
@@jannep6772 In some locations in Europe there's actually better fuel available. Germany has Aral 102 competition (ethanol free), Holland has some locations that sell 100+ (ethanol free) fuel.
Ethanol is the octane part in fuel but it tends to make the fuel burn relatively slow. Slow is a longer combustion period and that adds up to the actual heat in the engine. Better quality fuel burns quicker and therefore runs cooler.
Better fuel isn't just a higher octane value. Stuff like Sunoco, ELF, VP, Panta are completely different from the stuff you get at the gas station.
I think fuel quality, besides bad maintenance and bad habits, is the main reason of engine failure, you can compensate by running engines richer to keep them cool but you really want better fuel to keep the thermal drama down. Engines are running quite high rpm's and compression, there's just a really small amount of time for a combustion to happen, you don't want slow burning fuel, it runs hot. Adding 20% extra will cool it down a little but it's a bandage.
Best way to warm up a 4T racebike is to hold it wide open bouncing off the rev limiter in neutral to keep the motor running clean
;-)😅
Yeah, it's best to do it in your driveway early in the morning. The neighbors will love it.
@@twc9000 😎😎😎
@@twc9000 I find it to be more effective during midnight too
@@twc9000 the neighbors wont have to put up with it for very long ...it will make the sound of the first bike in this video and then it will never run again
..
As a ex shop owner I'll give you my reasons dirt bike engines blow up, it's quite simple. Alot of dirt bikes are owned by scallywags, they are not the sharpest tools in the box and have no idea about maintenance. So basically they smash the bikes head in and do no servicing, eventually the bike blows up, usually because of lack of oil. After you rebuild the motor for them they go and do exactly the same, even though you give them a strict running in instructions. Sometimes you have their bike in your shop for so long you have to sell it to recover your costs. The phone number you were provided with that you call to advise you will sell the bike no longer works because the guy who brought the bike to your shop is in jail. Once out of jail you then receive threats because you sold the bike. This is in the UK.
Fuckin Skallywags!
@@odyshopody9387 😂
This is very accurate 😂
@@limbo5463 🤣😂
Don't forget some of these guys like to ride crazy long wheelies starving the engine of oil mostly the four-strokes
It ends up being the same octane numbers, EU vs USA.
It's the method used to measure the octane what differs.
Been explained many times before.
Sell them before they blow up is the way to go?
I really enjoyed this video, very informative. You should make Brad a regular!
very informative ? lf you didnt know that you should change the oil once in a while and clean the air filter and splash some fresh gas in the tank is all that was said and never did the video answer the main reason 4t dirt bikes blow up ,,so if you own one sooner or later its going to self detonate because you still have not been told the real reason why all 4t dirt bikes will all fail that will never happen to a two stroke simply because they do not have any of the parts all 4t dirt bike engines have that causes to fail in the first place ..since you are a millennial who always rudely interrupt their elders and try to correct as you all believe we are to old to know anything ...so i say i know exactly what will fail in all four strokes that even after the parts are changed out their will come a time where those same parts will have to be changed out again ,,and if you allow them to go on beyond and fail they will cause more damage and destruction than the cost of and complete brand new engine ..and go now and figure it all out by yourselves as i am never going to tell any millennial anything at all about everything that you have been purposely lied to about that will cause you to fu
Much needed information to prevent the continuation of a common money sink hole in MX engine failure.
I wish to add when choosing a hi competition piston it will be from std.range of 13:1 average, becomes 14:1, that must run on its specific fuel. and should stamp a note alert to stay with all the ouners when selling.
other remedies can help reduce the heat by larger radiator and pumps, lower thermal fan switch, cooler in heat range spark plug, rich jetting or mapping, oil cooler in some exceptions.
Great video. Good to hear from the expert
This guy Brad is solid gold! I've also watched his engine rebuilds and wow is he impressive.
Maybe, except, that he putted the Main Reason on only the 6'th place.
@@bustjanzupan1074 he did not tell anyone the main reason 4 stroke dirt bikes fail , simply because he does not know or even have the slightest clue
.he did not even mention one reason why of the failures he has seen ! He is only a parts exchanger and not a diagnostic technician
@@bustjanzupan1074 he never mentioned the main reason all four stroke dirt bikes fail. That is the valve springs become too weak in a short time to keep the valves from contacting the piston at the extreme rpms they turn ..all so the tiny hardened steel pins that hold the stacked plates together of there hyvo style cam chains that turn extreme rpm causes the hyvo style cam chain plates to wear tiny notches on the hardened steel pins to cause just one pin out of the hundreds of them to snap into sending the cam chain through the bottom of the engine case at which time the camshaft has stopped turning with intake or exhaust lobes still holding valves wide open to come in contact with a piston that is still going up and down striking the valves 233.333~ times per second causing a domeno effect of major parts of the engine to go kafu¢ken Boooom party over time to buy a complete new engine that usually cost half the price of a new bike ...or spend a little bit more and have A.J. Waggner to shoe horn one of his BUILT CR500R or a CR538R insane strokers all billet cnc milled aluminium complete two stroke engines licensed by Honda with A.J.'s adapter kits made for each brand of 450 four stroke frames . What you end up with is a king of hill , track , and drag strip that can not fail from any problems due to all four strokes because the CR500R engine does not have any parts that fail in all the four strokes which makes the two strokes of today 100% more reliable if you know how to service and maintain a two stroke , it will live longer than you. And all the specs this joker in this video tells you about to stroke engine life is all his own made up B.S. as far as my information goes about two strokes come from a time of honda's very first two stroke that was designed by only one man who was the most world famous professional motorcycle engine designer and racing tuner of all times known world wide no other than Pops Yoshimura who designed built and raced the Honda Elsinore to several Japanese Championships and then in 1974 became the instructor at honda's R&D Training Center in Milwaukee where i became one of Yoshimura's students for around five years learning all the mods Yoshimura made to the honda Elsinore as they were developed over the following years giving me hands on knowledge of everything there is to know about all two stroke engines that i was required to know to keep my job while working at a honda franchised dealership that sponsored AMA pro motocross racing... to evolve into the CR500R that A.J. Waggner by licenses through honda for 25 years has been building two stroke engines from forged blocks of military aircraft grades of billet aluminum and using forged aircraft steel dynamically spin balanced and stuffed crankshafts and transmission gears, shifting forks , counter and main shafts, couplers and special oem machined spacers where they apply..modified billet water pumps and at request engine cases special designed to except common easy to get hydraulic clutch cylinders ..wait a second , why take my word for it who knows more than most about all two strokes , here is A.J. and his website with phone number to call and talk to the guru himself...i try to keep my comments as short as possible but as you can see i know too much and so little time ...now you know too much so if you will please show your pals your new information for in the future we can all be on the same page and ready for the next level up in two stroke tuning ..just remember two strokes by design are internally supercharged at causes their power band to make pounds of boost ...four stroke can only suck, bang, and blow (into dozens of pieces parts and parts pieces in one first and last KAFU¢KEN BOOOM)
BUILT500.COM
if for any reason you dont like to ride red he now builds engines in flavors of blue yellow and green as well
@@donniebaker5984 What are you on?? 😳 -NY
@@Davido50 the truth . at age 73 today i was at age 25 an apprentice of "pops" yoshimura the inventor of honda's first two stroke called the "Elsinore" ever heard of one ? i doubt it ! that was the game changer as famous as pops yoshimura rip . buzz off ass hole
Thank you for the tips it helps me out a lot!
Great advice!!
Just the video I was looking for
Thank you
I see so many guys start their bike cold and hold it to rev limiter
Dude my roommate has an older like 02 Klx 300. He fires that thing up and jams out giving it zero time to warm up hahah been doing it for a year or two. I told him you’re going to seize that bitch up doing that. But it hasn’t yet it’s actually quite impressive hahaha.
Really bad thing to do🤓🤙
@@Eddiep80he's lucky
Worst thing to do ever,man,y?😫😫😫🤯👁🙈🙈😱😮🤔😡💀💀
You guys have rev limiters?!?
*sad 2 stroke noises*
That was super cool! His experience and knowledge was obvious. Cool guy!
Lol, seeing the tmr cylinder brings back memories...had a cr250 with tmr cylinder and porting on race bike... good machine 💪
Phenomenal video!!! Loved it
Change the filter every moto. Change the oil every race. Never had an engine blow. Raced from 79-2001.
Great video man!
I have a 86 kx250. It ran with a cracked piston(not the best but pretty dang good) I have only put a new piston in it. The crank is original, I run pump gas (85 to 87, cause I’m broke) I now probably have at least 50 hours on it and it is still running perfectly fine.
I need to chime in here.. I have a different opinion when it comes to four stroke valves.. I suggest not adjusting the valves at all on bikes with titanium valves.. When the valves tighten up and the bike becomes hard to start imo tear it down and replace them because the titanium coating on the valve seats are only microns in thickness so if your valve has moved 3-10mm it's already though the coating and they need to be replaced.. I've seen this time and time again where people keep adjusting the valves and don't replace them and eventually they drop one due the shim thickness being too thin and not enough spring pressure.. The head of the valve sinks further and further into the head loosening the spring.. At high rpm valves float keepers fly off then its game over lol.. Also seen them pull the head of the valve completely off which doesn't end well either..
Every motor I have done with titanium valves I have had to send the head out with the new valves to have the valve seats recut, from my understanding the titanium coating is on the valves. Not the seats
Only two strokes 💪😜
VP Racce gas plus additive. Also don't forget Startron. It Mets out the varnish through entire system as it's an additive. It doesn't take much but you'll notice the bike starts right up and knowing you're not gumming up the jets and cylinder with horsepower sucking varnish! 2 and 4 stroke as well!
every 5 hours, i couldn't be on a 4T, i spend the whole day on my bike from 7 in the morning to 12 at night
very interesting video! Thanks!
man, look at the destroyed engine parts falling to the ground from that bike at the start!
Great content love it .
Am liking every bit of this content from kenya. My Serow has engine vibration at past mid rpm and am scared. Advice from you?
in the uk the fuel is pretty good, we have e10 (95 oct) that we wont even touch and e5(99 oct) that runs well
Great Q&A session
Brad is the best in the business!
Awesome video! Great info!
Great content
Great tips.
Get your arm good quick.
Cheers
Just wondering what kind of parts you use in all your motorcycles are they stock parts or different parts for your builds....
Thank you dude realy great advice
Happy to help!
My 2007 Yamaha WR250F seized at about 10,000km when a tooth broke off 4th gear and got caught somewhere in the bottom end. It made a real mess. I needed a complete bottom end. (new case, cylinder, crank, rod, piston, etc.)
what about microcracks developing over time more in cranks when engine is loaded too hard when cold?
how much should a rebuild cost. i know it changes with location.
fuel transports in your area pull out of the same area in the region..plus or minus some injected additives
I always change my piston every 10 to 12 hours on a YZ125. After 10 hours you can really notice the sound and performance are getting slowly worse, that's when its time to change it. Easy job, and you keep your engine fresh. Oil I'll do every 4 - 5 hours. Also clean your airfilter after every track day, that's saves so much trouble down the road.
Also a good thing to do, is to completely disassemble your bike once every year, clean and grease the parts, this way your bike stays just like new. Also it is a pretty fun winter or summer project 😉
Another tip for our two stroke lovers, dont mix your gas to lean. 1 liter to 40 liters of gas is a nice mixture. The more oil, the more power you get, piston rings will seal better creating a much better "bang" 😉
In my opinion,it's my opinion that's way to fast my friend believe it or not my friend had 340 hours on ktm sx85 before it blow up and my Kawasaki kx85 has like 160 hours i think and it's running fine yes maybe you don't get the same power out of it but i think 2 stroke if it's build right they can do easily 100-130 hours ,4 strokes i think easily 200 hours my friend has honda crf250 and he has like 170 hours and it still running fine it's my opinion and like honestly even if i want to change the piston every 10 hours i don't have that much money 🤣 like 10 hours thats like a week of riding and piston in my country are like 100 euros and avarge salary here is 1300 euros ,like its to much money for me to spent every week 100 euros that like 400 euros okey if i ride a little less lets say 2 pistons still 200 euros and then comes the gas and the oil and other things that breakes ,and you need to change brake pads🤯🤯,
@@gal184 Jesus Christ dude, 160 hours?? It's time for a change brother!
Well im sunday driver on enduro with 250cr from 97. Went to 40:1 and noticed incredible difference on performance from 32:1.
I dont prob have to change piston every 40h🤣
We have 99octane over here at the pumps 🏴
From my research... Chevron has the better gas.
I believe Shell is supposed to be up there, as well
Dudes! Good info Bro. Kiaora. Stay upright.
thanks dude!
You can get a mechanical cam chain tensioner to replace ktm's stock oil adjusted cam chain tensioner. You'll never skip a tooth again.
North America and Europe use different octane ratings, calculated differently.
Europe uses the "RON" rating and North America used the "AKI" rating.
RON is a higher number to it's equivalent AKI, but share octane qualities.
The vp additive is called vp madditive it works great. I run it with 91 non ethonal. Cleared the detonation up in my 300 tpi. It's my fav right now.
Non-ethanol kills detonation resistance. I tune big turbo cars for a living, 91 non ethanol is a lot more prone to knock than 91 E10, despite the same rating. 91 E free is like 88-89 with E10.
@@OtisFlint Or the 91 e10 is 91 octane gasoline with 10% ethanol added so it actually totals 92-94octane :)
10 hours for oil seems a little extreme to me also for 2 strokes with transmission oil or 4 strokes with 2 oil compartment when should I change transmission oil? Ktm Manuel says 40 hours
pekno video aj som sa dozvedel viacej informácií 😇
You had 98 RON in Slovakia which is equivalent to 93 octane gas in North America. 2 Strokes do love high octane fuel but any 93 pump gas at least here in Canada is not going to damage your engine.
I always ran ethanol pump gas in my 2022 gasgas 125 and it has 89hours no top end and still crisp
I always have 1% 2 stroke full synthetic oil in the gas on my 4 stroke engine, newer had problems on my Husaberg 650Fe and Honda XR 600 🇸🇪💪
Replace the valve springs and cam chain with stock OEM . No aftermarket stuff...put a small piece rope in the spark plug hole with the piston up against it
When intakes and exhausts are closed .this will allow you the change springs without removing the head..you can change the cam chain on the XR without removing the head or splitting the engine cases... The husaberg i know nothing about .
It may have bee hive titanium valve springs that dont wear out
Thanks guys a lot of racecars also run av gas have been imtrested in better fuel for my rmz 450 in Ca and the pump gas is trash
Av gas isn't that good a choice , Av gas has all kinds of additives needed for aviation use that are not good for getting maximum performance. A 50/50 mix of race gas and pump fuel is much better choice.
On my 2010 gas gas 200 I change the oil every 40 hours and clean the filter when it’s completely coated in dirt. 200 hours so far. runs mint
40😂😂
@@1991enduro hell yea
Why even run an airfilter, total waste! Just spray a shot of oil in the carb every now and again to collect the dirt.
@@markalan4026 more air flow! Might have to try that
Yep the quality builds , no need for cotton wool treatment .
First clip is Derek Anderson
What you gotta say about oil quality?
I have used Yamalube for years and I was told that Motul 300v Is the best ever oil but my engine blowed off after 60 thousand miles using Yamalube
What if i ride 4 strocke on the street ????? To change the piston?
thanks 😊
I own a ‘99 WR-400 F Yamaha . I’ve had it now for almost 22 years ( after buying it used ) and have beaten on it numerous times in all kinds of weather & terrain. I use quality oil, clean my air filter , and go over the bike usually before every ride , checking the usual stuff, coolant & oil level , chain , nuts / bolts , the spokes, tire pressures etc , and it has only had ONE valve adjustment, and since my ownership NEVER Had the top end apart for a new piston , rings , bore job , NOTHING. I swear this this is like a cockroach, I haven’t been able to kill it yet . Did I also mention it is street legal & gets ridden at freeway speeds to & from trail rides ?? That old 5 valve thumper has been the most reliable bike I have EVER OWNED , hands down. It’s jetted properly, starts cold usually within one or two good kicks ( ever since I learned it’s ways) and hot usually within a couple more or less using hot start lever on carb. It has a 3-1/2 gallon I.M.S. Tank and it still gets around 30-35 mpg when ridden hard , and around 40 mpg or more , at lighter throttle . I’ll probably never be able to afford a new $10, 000 plus anything dirt bike these days, so I try to take care of what I can currently on my own as much as possible. Oh , I also run a Scott’s brand stainless steel cleanable oil filter & have a spare one as well and a spare Twin-air brand air filter cleaned & oiled & ready for service times . Once swapped in the bike I then clean the ones that just came out & bag them in zip lock baggies for next go -round, usually in 500 miles or so . Take care of your machine & it will provide you with years ( decades ) of service . One more thing , DON’T pressure wash the crap outta your bike after each ride !!! This causes more damage than most people think due to water getting into places it shouldn’t. A little dust on things doesn’t do near the damage as a little water & eventually rust will . C-ya 😎👍
I have 900 hrs on my WR250f and it too is 100% stock and I raced it and ride in the rocky woods on PA. Valve adjustment is key if you run them at high rpms but if you run them in the woods they just keep going...
We have your exact bike. 99 WR400F and we bought it about a year and a half ago and we bought it supposedly "perfectly fine" but after we couldn't start it we took it to a dealer and discovered the head was over-torqued. Squished the aluminum head and the owner was able to revive the head and it has been perfectly fine since. We have done the HotCams auto-decompression cam to remove the fussy decompression lever and the bike is absolutely bulletproof. I agree with you. these early 5-valve Yamaha's are indestructible. I don't even know how many hours our motor has as for it never had a rebuild (on the previous owner and us). All that was done was oil changes and an air filter. We also took off the airbox snorkel to give it extra power. It also has a cheap Chinese carb on it since the OEM carbs are really expensive but after all of that it is a tough tough TOUGH bike.
@@kmx509 Just now saw your reply to my post about my ‘99. I don’t know HOW mine has survived my abuse all these years , but it has !! All you gotta do is give ‘em a little love & attention every now & then it seems. Enjoy your bike man😎👍
@@stephenmiller5023 For sure!
Got a 1987 TRX250X, pretty sure it was never torn apart, even the tires and rims were original when I bought it off the original owner, rear end definitely got damaged cause all the missing stuff but still ran til recently
For my bikes, 4 wheelers, and SxS, I have always put so much oil on my air filter that it is almost dripping off. Doing this I have to clean and re-oil the filter more often than my buddies. They say I am putting too much oil on it, but I argue that This is proof that my extra oil is catching more dirt. Am I wrong? Can you put too much oil on the filter?
Thanks,
Trav
Someone needs to send this to evan from the cboys
The only reason my 4 stroke knocked was because of a factory fault with the connecting rod. I checked the forums and all over, even yamaha said it
Yeah mine has a knock from the play in the clutch basket bearing
@@za5teeshftw709my 4t road bike yamaha has a clutch basket knock
KTM bottom ends that use a plain bearing last pretty much the life of the bike, or four times longer than needle bearing bottom ends. I had a 2013 250sxf for 9 years, track bike and never needed to change it. Only top ends at 80 hours. Never a failure or any problems. I change oil when it starts getting darker usually 6 hours or more. Use a nice air filter that is dense inside, even if it gets dirty outside no dirt will ever get in. Still have to clean it though, use dawn or filter safe cleaner. Never ever use gasoline to clean a filter.
does the gas degrade the foam? i know they feel weird after being in gas, but to me they always recover just fine when dry.
i use gas first, fully dry them, then use the soapy water last. then fully dry. i've also always used grease at the seal. most guys don't but i cant bring myself to trust no grease.
Is it the ethanol in fuel that is making it bad? I use ethanol free 90 octane in my 450 and avgas in my 2 strokes. Is ethanol free 90 octane goon enough or should I switch over to avgas in everything?
I do the same, I think its ok
not me over here rocking a 04 yz250f after putting 400 hours on it since i bought it and it had unknown hours on it and ive never takin the valve cover off it and it is perfect
Modern dirt bikes blow up because there's too many strokes. Cut the strokes in half & it's amazing how much more durable the motors become...
Good man!😎🤙
If i look at my valves 3 are slightly proud when closed like they are supposed to be but one intake is sat flush. Do you think ill get another race out of it ?
You are not giving up enough information to make any kind of a judgement call on engine life ..how wide are the contact of the valve face to valve seats ? How weak have the valve springs became ? How much slop is there in the cam chain links all pushed together and them pulled apart to see the slop in distance ? Is the valve that is deeper in the head than the other 3 needing the clearance adjusted more offen losing clearance
I agree with Brad. He has seen it all and of the 4000 motors I would say 100 are mine 😂
What about non-Ethinal?
Start off thay video my crf250x sounded like that what would it be
Number 1 they are 4 strokes more moving parts more complicated, easy fix buy older 2 strokw
hey, I have 2001 ktm exc 400, i changed oil and im running it for about 30h, i dont ride hard at all just cruising down the forest, couple hours ago the oil was clean, now it got black, should i change it still that often, because if the oil is black is not bad but it has gas in it thats burnt
low RPM trail riding makes it all less critical, but yeah... 30 hrs is a bit too long.
just think about clutch plate and gear wear particles running through your cam bearings piston skirt... you get the picture
My little CR80 requires 93. But you're saying all 2 stroke bikes should be burning atleast 100 octane? I thought you need the right compression for certain octanes.
For a 300 2 stroke trail bike, what are the advantages to running avgas or race gas if the engine isn’t detonating?
Zero.
Compression ratio
Carbon deposits shorten engine life. Low octane in a 2t will cause more carbon deposit..when you hear an engine pinging that is spark knock ...when detonation happens you can not hear it as its canceled out by the sound of combustion.. and 2 strokes are internally super charged when they begin running in their power band
..so 93 octane gas and a shot of 106 octane booster from autozone works ...but dont spare on your two stroke oil ..mix yamalube R 100% synthetic one pint bottle to five gallons of gas
@@OtisFlintfor you that goes for all engines just feed them what ever ..you dont have a clue
Avgas has anti freeze additives
I've learned all this the hard way
Conclusions go get a 2 stroke I prefer 4t but it's cheaper and easier less moving parts see
Yes , I love 2 strokes for their simplicity and ease of maintenance. Sound great too
I think 2 strokes are more fun also because they are very light and I can wheelie on it easier cuz of the weight
@@WealthMafiiayeah i gotta 4 and 2 and the 4 is wayyyy easier to wheelie cuz as soon as u get in the powerband in a wheelie on a 2 it scares the balls outta you
“Ktm you can go a bit longer” LOL!
Just checked my 2008 Rmz450 crank, had the bike since new. Still half within tolerance. Full synthetic oil almost every ride only done 1 piston and cam chain
How many hours on her
I got a 2016 kx450f with like almost 200 hours and it runs amazing im thinking about doing the piston but i dont think i have too cuz the compression still feels crazy
@@Blocanbentlyyahu dunno lost count around 400hrs. Only other bike I have from new is a 2014 yz250...love it but it cant compete on cost per hour to ride, strange given we all think it should be cheaper. Have a 03 rm250 and a klx250s. KLX just ate a cam,just got it going again ....great for night time slays in the forest with a light bar.
He’s right about Ca gas with Ethanol. It’s crap for engines. My bike and lawn equipment all see VP race gas. Cut my lawn time down two seconds a lawn
I’m in ca should I still run race gas if I only go to ocotillo wells?
no, just premium.
My trx450er is at 500 hours still on original top end and everything
can you tell me engine hr life and valve adjustment intervauls trail riding on xr650r ?
adjust the valves every 5 years of easy riding. the engine will last forever if you do the oil and filter often and run good gas.
I change my oil and air filter after every ride. Oil filter every other change. Oil is cheap compared to a new KX 450 engine.
Hello guys, I’ve been looking for an answere for some time. And have been confused on buying a two stroke or 4 stroke, overall I love both.
But I have heard that two stroke tend to blow up faster, is that true?
it used to be true up until about year 2000 when all the MX bikes switched to high performance designed high revving 4 -strokes... which blow up more often than 2 strokes if they are not treated properly, as per this video.
Havent watched the vid yet, but just gotta say, change ur valves. Its just as important as cam chain. Mine blew up because a valve broke of and it ruined alot.
98 oct in Europe is exactly the same as 91 in USA. fun fact.
Good info as always. When I used to race MX, I ran pure AV gas that had lead in it. I haven't bought any in awhile, a long while. Does the AV gas still have lead in it? Ride safe my 2 wheel friends.
I've told sooo many of my friends about the old avgas. And yes its still leaded
@@MrSuperflydude I also used to run it in my 69 Roadrunner on Friday nights when we cruised the strip.
There's avgas with LL at the end indicating "Low Lead" but I think there are unleaded alternatives too. The lead protects the engine parts so they still use it to be extra safe with aviation :)
I always ran a 50/50 mix of AV-gas & whatever 91 octane premium fuel I could get in my Yamaha 2 strokes ( RD -400 & YZ’s ) and Never had any issues once jetted correctly . Made a huge difference out playing in sand dunes on my old Tri-Z 250 3 Wheeler too . 👍
Don't use 100LL. We don't need any more lead in the air. We need to wait for the dinosaur that is the FAA to approve unleaded recip fuels to be used.
Is it worth for me to rebuild my 2014 Yamaha bolt motor? Or to just buy a new one?
for sure rebuild it. should only need... piston/rings, valves and cam chain. only need to worry about the valve seats and the rod after about 400 hrs.
but wait... did you mean a boat or a bike??? if you mean boat... wrong forum to ask.
I only run VP and pump gas mix and I use all up that day...
In a four stroke ?
I’ve stopped pump gas altogether. Ethanol is so bad for engines and seals
Hahaha, when it comes to a part where you mentioned the fuel i was wondering about europe gasoline, where i can take 100oct gas from a pump.... And then host mentioned that he is from slovakia... It all came clear... ;)... Greetings from Czech Rep my mate...
Ktm 500exc trail riding - I only charge my oil every 20 hours (300miles) never had a problem 3000 miles later.
Avgas 100LL is cheaper than petrol in my country due to the heavy taxes on petrol.
And I live about 8min from the airport.
1: 4-stroke, 2: fast warmup, 3: lack of maintenance, 4: plating gone, 5: wrong jetting, 6: no oil, 7: Vertex piston
Really good and informative video. I was quite supirsed by amount of hours you can go on 4 stroke before rebuild - 100 hours on 250. I've heard that only once and most of the people I know says that 60 hours is maximum safe value for 250 used on MX track.
It depends how you ride but 100 on 250f sounds ok for weekend warriors
I'm average weekend warrior riding on passion, not skills and strength. :P
Thanks for reply and greetings from Poland close neighbourhood of your origin country- Slovakia. @@dirtniron
On 450 he says 150-200 hrs for a complete top end rebuild or just a piston ??
don't quote me but i think he means... piston/rings and cam chain, plus adjust valves.
replace valves after they need adjusting two or three times.
Change your oil every 10 hours? thats like every time you ride lol. Thats like changing the oil in your car every 100 miles.. lol I had a 2007 honda when i was a kid, and NEVER changed the oil in it in like 3 years and it was fine... I would never do that now.. but my point is, i think changing your oil every 50 hours or so is probably not gonna hurt it. Unless you do nothing but redline your bike maybe, then maybe more often lol.
I can understand an improperly fitted air filter letting dirt in, but why would a dirty air filter let dirt into the engine?
I can only assume the dirt is migrating through the filter
@@stevesmith756Yes Sir! It gets so saturated with dirt, it eventually is pulled through the dirt ridden pores. With a quick check before EVERY ride! Also, all the youngsters, stay off the rev limiter everytime you get in the air. It doesn't do much, and you don't have the luxury of motor rebuilds every ride like Haiden Deegan...lol.
Yup all that rpm on an unloaded engine is really bad. Bad habits
The mans right.
made in austria is that one , o)
As someone who lacks knowledge i ask, is there any difference between a 4 stroke quad vs a 4 stroke bike in maintenance?
I do not hear any quad guys needing to replace pistons at X ammount of hours.
in most cases, a huge difference, yes. think of it as a farm tractor engine, vs a race car. the engines are not comparable. most quads have low revving torquey 4 strokes, while the MX type bikes all run a high RPM design that is much more demanding about perfect maintenance. most trail bikes also use the old school engines.
if its a quad, you need to set the valves once a year and change oil as often as you can, but the main thing is to get the engine rebuilt when it starts using a fair bit of oil. it will be burning more oil due to cylinder and valve guide wear.
so in short, quad riders can just ride and stay happy, but modern MX bikes need everything to be perfect, as this vid well states.
@@yukonjon5964 Thanks for the response!
@@martinsk8798 yep. first thing to go on a quad is the cam chain, and the cylinder wears enough that it burns a lot of oil even though it still has good compression. can burn up all the oil fast too, so gotta watch that.
can normally hear the cam chain sound once the tensioner reaches its max. mainly when letting off the gas when parked.
@@yukonjon5964 Understood, will keep an eye out, for now I only did 7 hours to my quad (winter here so can’t ride much)
@@martinsk8798 yeah your safe. it takes years and years to wear quads out. i've seen guys have the hour meter show 2000 hours and no one ever touched the engine. on a Honda.