Hi,

 

I rode my mates 08 rev 3 125 in a trial on sat night. it ran fine for two laps then died. There were two small stream crossings but it ran fine after that and performed well all night then  Would not start again.

 

I then washed the bike sunday morning, started fine with choke.

 

Since then when my friend has stripped the carb, new dry filter in, dried out the airbox then gone to start it, it has run but with hanging revs. Tonight it was screaming full revs and then would not shut off, kill switch and plug cap off, still going balls out.

 

Any ideas??

 

They have dried stator out behind ignition cover, checked airbox boot for splits, taken reedblock out ad inspected all that area. Throttle, slide, jets, all seem good.  Theres nothing obvious they can find.

 

We'd really appreciate some advice before it ends up going to a shop to be fixed

 

Thanks

 

 

 

 

 

It has a keihin carb if that matters?

Check again that the carb slide is closing fully, Might be the cable pulled out of the carb top slightly.

as mentioned give the cable a little wiggle where it goes into the carb, had this happen alot, even on newish bikes. it needs to sit fully back into the tube that comes out the carb. also place your finger on the side of carb/float bowl and with the engine of open the throtte to full and let go of it, you will know if it has returned fully becuase the carb will make a light clunk as the slide bottoms out. also take the piliot jet and put it in carb cleaner and let it soak, then blow it out with compressed air, it has to be properly blasted through, the 125 jet is so small. my piliot jet on my 125 gets clogged quite often and sometimes causes "hanging" revs.  hope you can make sense of all of that! good luck!

A similar thing happened to my old mont 2t years ago.

 

that too was while I was messing about with the throttle cable at top of carb.

 

So if there was a leak on the crank seals it wouldnt be enough to set the bike off screaming each timeits started?

can a leaking crank seal cause this over revving?

im not sure on that one, someone will know.... have you checked what the above posts said?

My mate has taken the bike to Juan Knights shop, will find out soon whats wrong.

It was the pilot jet that was blocked. Simple