Had the same problem on my o3 kx125 sorted problem bike still run poorly chased jetting back and forth for a while some days it’d be on the money and running perfectly others running dirty again was ok on the pipe but putting through woodlands or road use was a no go as it kept loading up and fouling plugs the tuning kept changing on it with weather change I’ve never had trouble jetting or setting carbs up on bikes but this carb gave me the run around big time I bit the bullet and imported a lectron billitron 38mm bloody expensive but worth every penny bike runs crisp off the bat for any type of riding I’m doing
@@danpoxon2425 Thats good news, glad you got it straightened out. We took the bikes out this weekend and the wifes YZ125 is running as good as new with the new carb, sounds so clean and crisp now.
@@stravis3269 Yeah my friend Dustin (the guy who helped me with the YZ250 pipe review) said the same thing. He said all he heard online was good things about the lectron. He bought one and tried it. He couldnt get it to run better than his stock carb so he went back to the stock carb and says he wasted his money. I tested the bike with the lectron and it rode good, didnt do anything really wrong but just seems to lack a little of that liveliness that the stock carb provides on the YZ250. They do work but I do feel the stock carbs can be more finely tuned.
As it's not listed nor shown in the service manual or any online OEM parts fiche, not many realize there's also a needle jet (not that same as the jet needle) deep inside this carb, it's accessed by removing the main jet and it's holder nut. Incorrectly indexed versus the 'atomizer' tower (btw there is a small notch in it from the factory) the engine will run poorly from 1/4 to 1/2 throttle. The needle jet has a notch machined in it's side which is used to properly index it using the small brass pin in the main jet tower.
Man, that stinks if that atomizer thing is an unreplaceable wear item. I know the needle jet and the main jet holder are replaceable cause I replaced both on my '05 yz125's Mikuni TMX38 carb in an effort to stop fouling plugs (which ultimately ended up requiring replacing the jet block gasket with the JD Jetting version once it came out a year or so later). Would be interesting to measure the ID of that atomizer thing. I know it's a precision thing, but could always just find a tapered needle that drops down into the hole and compare how far the same needle drops into the new carb's atomizer hole compared to the used/worn carb. Wouldn't provide any measurable numbers to the inner diameter but at least might illustrate a confirmed difference.
Yeah would be interesting.But its so hard to even get a eye ball down in there lol. Good news is we took the bike out this weekend and its running super clean and crisp now.
Another great vid bro! I think I'm chasing your shadow on that carburetor issue aswell.. I might just pull the trigger on that exact carb you bought. I am curious about the jet block gasket in the new carb. Should the OEM gasket be replaced with the JD gasket right away?
Thanks! Yeah that carb for 400 on ebay is a awesome buy, same carb yamaha sells us for less though. Im going to say just leave the stock jet block gasket in the new carb as long as its working well. I don't like to mess with something if its working well lol. However down the road if it goes bad then replace it with the updated JD jet block gasket
Hey mate. Just doing a top end in my crf450 after watching your videos. I’ve noticed some small cracks in the case and was wondering if I can send you some photos somehow to get your opinion. Thanks
@@tndeere2 I like the Mikuni better myself. never owned a lectron but I have worked on bikes that have had them and also riden them. I feel the OEM type carbs allow for finer tuning. I also dont like how the lectron looks, kinda cheap looking. There are guys in here who have had success with them and its gotten them up and going again. But I just cant do it myself, and the clear float bowl looks gimmicky to me. They are simpler to tune in and that does help guys out though. That being said I will be putting one on a KTM 150 for a friend tomorrow at the track who just needs his bike up and going.
@@UpAllNight91 get lectron carb bro an ur bike will run better than it ever has I went through same thing but worse with mukui carb junk just cause upallnight don't like them doesn't mean that there for everyone I love mine before I bought my lectron my bike was running bad I even got mad threw a rock at my bike put dent in frame all because of mukui carb now bike running good I see the dent an think of what junk mukui carb put me through they don't hold up well like lectron
@@michaelgarland579 My yz125 is probably the best running 125 I have ever riden. Super crisp and clean, razor edge sharp running. Honestly I don't want to change a thing on it. Its one of them bikes that whenever anyone rides it I can hardly even get them off it lol. Dont wanna change a good thing.
Love your work bro, i have this carb from a cr250 low hours. Allways rich. I think honda came with different internal specs in their tmx model carb. I put a s7 needle or sleeve from a Yamaha it seemed to help a little. But these carbs are problematic from what i gathered. I just deal with it. Would it be better to be rich than lean i guess.. but a leaner condition would run hotter and more power in my opinion
Thanks! Yeah Hondas where often sent out on the rich side, they where like that even since like the 1980's. Your right its better to be richer then leaner for engine protection. But knowing me I would tinker and tinker till I got it right on lol. Sometimes OCD can be good, but dam sometimes its torture lol
If a rider is working the motor hard, you can either go up on the main or run higher octane. Both achieve the same thing, helping the combustion chamber stay cooler under WOT
Same issue with my 05 Kx125. Guess I’ll be ordering a new carb. Great job as always
Thanks!
Had the same problem on my o3 kx125 sorted problem bike still run poorly chased jetting back and forth for a while some days it’d be on the money and running perfectly others running dirty again was ok on the pipe but putting through woodlands or road use was a no go as it kept loading up and fouling plugs the tuning kept changing on it with weather change I’ve never had trouble jetting or setting carbs up on bikes but this carb gave me the run around big time I bit the bullet and imported a lectron billitron 38mm bloody expensive but worth every penny bike runs crisp off the bat for any type of riding I’m doing
@@danpoxon2425 Thats good news, glad you got it straightened out. We took the bikes out this weekend and the wifes YZ125 is running as good as new with the new carb, sounds so clean and crisp now.
Great update to a great vid. I like the graphics on your wife's 125.
Thanks! She gets so many compliments for that bike lol. I joke with here and call it beer can graphics because of the shine it has lol
I bought the cheaper carb for my bike. I dont think its genuine because it comes with "keihin size" jets, but it works well for me.
What carb did you go with I’m looking at one for my yz250 it’s like $40 on eBay
@@IdahoDirtBiker9908 the one he showed in the video (180$) i just got genuine jets and works like a dream
Thanks for the insight on that cheaper carb. Glad its working for you but dang that would be a great price if it was a true mikuni.
@@UpAllNight91 I heard a lot of good reviews of a lectron, my carb is like new and dumps fuel like crazy but I am smoking out everything
@@stravis3269 Yeah my friend Dustin (the guy who helped me with the YZ250 pipe review) said the same thing. He said all he heard online was good things about the lectron. He bought one and tried it. He couldnt get it to run better than his stock carb so he went back to the stock carb and says he wasted his money. I tested the bike with the lectron and it rode good, didnt do anything really wrong but just seems to lack a little of that liveliness that the stock carb provides on the YZ250. They do work but I do feel the stock carbs can be more finely tuned.
As it's not listed nor shown in the service manual or any online OEM parts fiche, not many realize there's also a needle jet
(not that same as the jet needle) deep inside this carb, it's accessed by removing the main jet and it's holder nut.
Incorrectly indexed versus the 'atomizer' tower (btw there is a small notch in it from the factory) the engine will run poorly from 1/4 to 1/2 throttle. The needle jet has a notch machined in it's side which is used to properly index it using the small brass pin in the main jet tower.
It's a sleeve the needle sets in.. A little wear it will make a rich over time
@@stravis3269 Yeah there is no way to remove that sleeve and replace it that I know of at least.
Man, that stinks if that atomizer thing is an unreplaceable wear item. I know the needle jet and the main jet holder are replaceable cause I replaced both on my '05 yz125's Mikuni TMX38 carb in an effort to stop fouling plugs (which ultimately ended up requiring replacing the jet block gasket with the JD Jetting version once it came out a year or so later).
Would be interesting to measure the ID of that atomizer thing. I know it's a precision thing, but could always just find a tapered needle that drops down into the hole and compare how far the same needle drops into the new carb's atomizer hole compared to the used/worn carb. Wouldn't provide any measurable numbers to the inner diameter but at least might illustrate a confirmed difference.
Yeah would be interesting.But its so hard to even get a eye ball down in there lol. Good news is we took the bike out this weekend and its running super clean and crisp now.
Another great vid bro! I think I'm chasing your shadow on that carburetor issue aswell.. I might just pull the trigger on that exact carb you bought.
I am curious about the jet block gasket in the new carb. Should the OEM gasket be replaced with the JD gasket right away?
Thanks! Yeah that carb for 400 on ebay is a awesome buy, same carb yamaha sells us for less though. Im going to say just leave the stock jet block gasket in the new carb as long as its working well. I don't like to mess with something if its working well lol. However down the road if it goes bad then replace it with the updated JD jet block gasket
@@UpAllNight91 I'll keep that In mind! Thanks and ride safe bro!
Hey mate. Just doing a top end in my crf450 after watching your videos. I’ve noticed some small cracks in the case and was wondering if I can send you some photos somehow to get your opinion. Thanks
Sure. You can email them to upallnight91@hotmail.com
Good video my lectron carb doing good
Thats good news.
Trying to decide on the lectron or a new Mikuni for my 05 KX125 as mine is running rich now
@@tndeere2 I like the Mikuni better myself. never owned a lectron but I have worked on bikes that have had them and also riden them. I feel the OEM type carbs allow for finer tuning. I also dont like how the lectron looks, kinda cheap looking. There are guys in here who have had success with them and its gotten them up and going again. But I just cant do it myself, and the clear float bowl looks gimmicky to me. They are simpler to tune in and that does help guys out though. That being said I will be putting one on a KTM 150 for a friend tomorrow at the track who just needs his bike up and going.
@@UpAllNight91 get lectron carb bro an ur bike will run better than it ever has I went through same thing but worse with mukui carb junk just cause upallnight don't like them doesn't mean that there for everyone I love mine before I bought my lectron my bike was running bad I even got mad threw a rock at my bike put dent in frame all because of mukui carb now bike running good I see the dent an think of what junk mukui carb put me through they don't hold up well like lectron
@@michaelgarland579 My yz125 is probably the best running 125 I have ever riden. Super crisp and clean, razor edge sharp running. Honestly I don't want to change a thing on it. Its one of them bikes that whenever anyone rides it I can hardly even get them off it lol. Dont wanna change a good thing.
Love your work bro, i have this carb from a cr250 low hours. Allways rich. I think honda came with different internal specs in their tmx model carb.
I put a s7 needle or sleeve from a Yamaha it seemed to help a little. But these carbs are problematic from what i gathered. I just deal with it. Would it be better to be rich than lean i guess.. but a leaner condition would run hotter and more power in my opinion
Thanks! Yeah Hondas where often sent out on the rich side, they where like that even since like the 1980's. Your right its better to be richer then leaner for engine protection. But knowing me I would tinker and tinker till I got it right on lol. Sometimes OCD can be good, but dam sometimes its torture lol
Do faster riders often need richer jetting all arround or just on main jet?
If a rider is working the motor hard, you can either go up on the main or run higher octane. Both achieve the same thing, helping the combustion chamber stay cooler under WOT
@@UpAllNight91 do faster riders need richer pilot and needle to?
@@user-ue3ku6qb3j Usually just a richer main is all thats needed
@@user-ue3ku6qb3j For the YZ125, a 37.5 pilot, stock needle in stock postition, and anywhere from 430 to 450 is good.
Could that gasget bad cause it to be lean