New top end and now no power???

[joshualeeusmc]

Here goes.... I have a 1995 250 Exc, bike was running good, but was loosing the snap. I tore it down and found the head pipe had about a quater inch of carbon built up all the way arround it, the power valve was so plugged with carbon it looked organic, and the piston had some serious signs of blow by. I also took of the flywheel cover to check for any oil and sure enough the seal from the clutch lever was blown. Two weeks and $300 dollars later I had a new weisco pro lite piston, seal for the clutch actuater, and paid the Local KTM shop (the only KTM dealer on Oahu) to clean my powervalve. Now you have the history here is what is going on. The bike feels good down low and has a decent mid range hit, but nothing spectactular compared to what it had before the rebuild. On the high end it has absolutely no power, it falls flat on it's face. The bike will rev all the way up very nice and crisp when it isn't in gear but as soon as there is a load on it power is gone.

What I have checked
-demension "x"
-demension "z"
-power valve operation is good
-tried a wide variety of jetting, and have had the best results with a 50 pilot, 3rd clip on the neddle, and 172 main, Carb is a pwk39.
-repacked siliencer
-Arrow on piston is pointing to the exhaust port
-compression is good

Am I missing something? Please share your thoughts.
(I also placed tis in the General Maint forum, with no response.)

-Joshualeeusmc

 

[SirHilton17]

maybe it just needs to get broken in mine always doesnt have as much power at first

 

[ellandoh]

powervalve assembly ??? sorry didnt see you checked its operational already

 

[bclapham]

piston back to front? gasket/air leak? reeds in wrong??

 

[joshualeeusmc]

It was the timing, the woodruf key sheared off. Got a new one and set the timing, now she is a fire breathing woods machine!

 

[Speedfreek]

Thats great,easy fix :ride: