Hey all I am very new to pit bikes and even newer to this forum. I just picked up a 125cc off of craigs to use as a pitbike as well as to do a little stuntin. Anyway I have an issue... There is hesitation and jerking that goes on right when I gas it. After it gets going it seems to be fine. When looking at the chain while riding it bounces allot near the front sprocket. Also the chain has come off a couple times. I tried tightening the chain and making sure the rear wheel is on straight. Not sure what else to check, We pulled off the front sprocket because it seemed loose but it didnt seem to be the problem.

There is an issue with a broken mount on the Stator but it has been rigged to work. any chance the issue is with that?

I have been told that it is possibly the clutch slipping but it isnt a smooth slip it is very jerky.

Anway any input would be greatly apreciated. Thanks allot in advance.

 

Is it jerking or bucking?

 

Kinda jerking. But could also be bucking. Sorry if thats not much help

 

BTW engine is running smoothly not miss firing or anything, it just seems to be an issue with transfer of power.

I am willing to do whatever is needed to fix and have some mechanical experience. Kinda wondering where I should start?? ie burnt clutch plates, chain tension, etc

 

Might want to try fix the obvious problems first. Later rebuild the carb. You bought the bike used and don't really know how the previous owner took care of it.

 

Does it have an auto clutch or a REAL manual clutch?


If it has an actual clutch, then you probably DO have some issue



if it has an auto clutch.. tahts just how they feel.. They jerk when you hit the gas and the bike starts to go.

Also, the front sprocket is supposed to be lose, it is just held ON but not tight



about your chain coming off. idk.. Sounds like its either way to lose, or the wheel is crooked.


Does it have a REALLY long swingarm on it? If so, does it have a 'chain roller' to keep tenson on the chain?
Problem with these little bikes with BIG swingarms, is you gotta run the chain extremely lose, that way when you bottom out on jumps, the chain doesn't get TOO tight and break

 

It has an actual clutch. And it also has an extended swingarm. It does have a chain roller that presses it up against the bottom of the swingarm(creating a indentation in the metal) And Yeah a friend of mine has a XR50 with the Semi-Auto and it feels totally different than that for sure. Also the rear wheel was a little crooked when we got it due to a stripped adjustment nut that we have now replaced and straightened the wheel as well. when you put it in1st and start to drop the clutch it shakes and seems like it is Jerking or slipping. then as RPM go up it smoothes out and runs great. then you shift to second and start letting out ther clutch again and jer jerk jerk then smooths out again. Also when you are decelerating with it in gear and the clutch not depressed it kinda jerks. When driving next to the bike you can see the chain is jumping allot, mostly near the front sproket. Thanks allot for any input, I really apreciate it allot.

 

The chain might still be too long and you might have to much slack on the chain if it is jumping in the front. You might want to see if you need to take a link out of the chain to tighten it up a bit. Don't tighten it up too much because you need the slack when the bike bottoms out from a jump.

If that it not the case you need to start looking at the clutch.

 

What he said....When my chain gets too lose I notice the hesitaion feeling esp when im up on one.