My friend has a CR125. Fresh top end pipe and reeds. When he first startes it up it runs good, but then when it gets warmed up it it seems to get really rich and alot of smoke comes out, and it spudders severly. I though it was a jetting problem. Went down in sizes and ran even worse! Hes cleaned the carb out about 5 times, and has adjusted the clip every position. The crank seal is good also so its not leaking oil. (he mixes 32:1) The reeds are brand new.

Dose anybody have any ideas on what this could be.??

 

I used to have an 89 kx 125. It would start cutting out at a bout 1/2 throttle. I ended up taking it in to a mechanic. He said everything was fine except the inside of the carb eas wore out because of all the crap going thru it over the years.
Hope this helps.

 

thanks, Dose anybody think it could be form a worn out silencer so it dosent have enough back pressure? or could it be from the eletrical system mabey??

 

he may not be getting enough air flow. try taking off the air box lid and gettin a high flow air filter. my quad seemed to run lean but when i ditched the filter box lid, it ran fine. didn't even have to adjust jetting.