no top or bottom end power just mid

[todd1985]

i have a 99 yz 250 and i have no power in the bottom end or top end just mid and i can figure out how to fix it. for some reason it seems to be running rich but i have hear everything from jets to ignition problems. can anyone help?? it sucks cuz i gas it and it takes a sec. or two to get power :(

 

[BigRedAF]

Reeds might help in this case. Consider Boysen Super Stock replacements, they're pretty cheap to replace and may solve your problems.

http://www.boyesen.com/cwo.php?stor...e=YZ250&submit.x=43&submit.y=18&submit=search

 

[todd1985]

oh crapy i forgot to put it on there i just replaced them lol and i those r the exact reeds i got to weird i was hoping that was the problem but nope i also went down a size in my main jet and i cleaned my power valve out too i really just want it to run right again

 

[BigRedAF]

I had a 99,00,02,03 YZ250. They ran great and I never had any issues at all.

You need to rule some things out:

Do a compression check, look for 180+ psi on a stock YZ250. Make sure your using fresh premix, replace the plug, check for vacuum leaks around the intake, re check your power valve linkage, clean your air filter. If all of this checks out fine you will need to test the coil and ignition systems. A shop manual will give details for the trouble shooting process.

Good luck...

 

[todd1985]

ok sweet thanks man

 

[AwfulSmokey]

You are supposed to lean your bike out a little when installing aftermarket reeds. Did you have this problem before installing them? If so, you were rich then and even richer now. Try turning your air screw out 1/4 turn and see if it improves, if it does just play with the screw until it gets right.

 

[todd1985]

well actually i did but i put new exhaust on it and i think thats when it started but not to sure cuz i only road it once b4 i put the exhaust on it and i checked my compression its good and baught a leak down checker and its good too i am going to try and go down jet sizes but i don't know how many i have reeds and full exhaust(pipe and silencer) on it but i don't know how many sizes to go down it was at stock and i just went to the next step down in jets but it didn't really do anything what size should i have??