Problems help!

[bryceyz250f]

Well I finally got my bike to run it runs fine until I put a load on it and mash the throttle. I have a. Brand new piston and rings in with brand new cams/valves I am so lost with this bike anymore if someone can help. Please do thanks.

[AHill11]

What exactly is happening when you "mash" the throttle? Does it seem like a carb issue? Or clutch or something internal? Also what bike n year?

[Kuhny]

hi i had YZ 400 f it was real bad on plugs would ok till u try to go flat out ,i would just put new plug in and all was good , i spoke to guys at bike shop and was told older YZ were like that , i asked about buying bettter plugs and got told not to waste my money just have a good stock of cheap plugs . but i have had it in once to fine tune jetting

[bryceyz250f]

Well its an 01 but even if I dump the clutch at high rpms it bogs

[carsonG97]

Sounds like a carb issue. I have an 01 yzf also and I've never had any engine issues at all.

[bryceyz250f]

I know its a carb issue but need to know what about the carb is bad

[flyandride]

Sounds like a typical dirty carb problem.  Jets get clogged with crud and varnish.  The varnish is something that gas leaves behind when it dries out.  Take the carb off, take it apart and clean every part.  Don't use carb cleaner on rubber parts, they can get soft or turn to mush.  I use strands of copper wire in the jets.   Don't take apart the carb body.  There's torx screws inside the carb, don't remove them.  Soak the carb body and rubber parts in Pine Sol.  Rinse with hot water and blow out with compressed air.  Check the tank and fuel line for crud also.  

[ickfinger]

Check AP diapragm/adjustment

Edited October 20, 2013 by ickfinger