Honda cr125 smokes, less power

[Horrorbusiness]

Hey guys!

I have an problem with my -00 honda 125 that makes me rip off my hair! The thing is that the bike starts fine but it smokes a lot. You can also notice that when start riding it. But if you open full throttle and and take out the maximum from engine. Then you can feel that it work well. But if you let go off the full throttle and go to idle again, the smoking starts and you feel that you are loosing power. Then you have to drive a few minutes again with full throttle and then you feel it´s working again.
It feels like it has something to do with the rpm. The engine is totally rebuilt with new cylinder and piston. And it had the same problem before the rebiuld. The carburator is adjusted in factory settings, and also the main jet is original. The aircleaner is also new, and the sparkplug. I compared the spark of the plug to another bike -99 honda, and it seemd like that bike had a stronger spark. I also have tried different 2 stroke oil. I would be realy happy if someone could help me on this.
Thanks´
Teemu

 

[_JOE_]

Possibly a right side crank seal. Could be a worn main jet/needle. Did you set the float height?

 

[Horrorbusiness]

Thanks Joe,

There are new seals on the entire machine, so I dont think it´s that... I´ve been reading here on this forum about the jetting, and I might have to try adjust the carb. The float height should be ok, I checked it. My first thouhgt was that the spark is somehow weak on low rpm´s. I don´t know if that´s even possible?

 

[_JOE_]

Weak spark at low RPM would be difficult to diagnose. Rule out everything else first, jetting is good idea. Then, if it still runs poorly, go through all the pinpoint tests in your service manual for the ignition.