bike just wont run right, need help!

2005 yz 144. I got the bike a year and a half ago. I never toucheed the jetting. Bike has always started up first or second kick and ran great. The motor blew on it and had full top and bottom end done with maybe 20 hours if even that on it. After rebuld bike ran really amazing. I weight 200+ with gear on and the front end would wanna come up some.

All of the sudden the bike just is not running right. It has a powerband but no "hit" The bike is just down on power. I had to replace the right powervalve and i had it re grinding to fit the 144 cylinder. its not a percet match of the left side but its not bad. When im riding the bike, say just crusing down the road with quater throttle the bike is almost sounding like its loaded up but its not. If on a stand and i rev it, it sound totally crisp and fine.

I guess the best way i can descrbe the power issue is it almost feels like the clutch is being held in slightly and i cant get full power. I can literlly hold the bike wide open with clutch pulled in in a corner and not worry about something happening. I cleaned the jets twice. Put fresh gas. I put new clutch spings in and measured the fibers and they were just in spec. I put a new plug in I have never fouled a plug in teh bike but once in a year and half. I fixed the powervale problem also i had.

I really have no clue what is going on here any ideas i appreciate.

oh and i put a new ring on the piston and i new and freshly pre oiled air filter

Check your reeds and check to make sure your exhaust is clear. What oil are you using? Some oil has additives that will make your clutch slip. If that is all good, I would check the ignition system.

Reeds are good I checked them. I use Honda oil 10 w40. I will repack the muffler.

Check your reeds and check to make sure your exhaust is clear. What oil are you using? Some oil has additives that will make your clutch slip. If that is all good, I would check the ignition system.

Check the stator, i had an aftermarket one break down on me recently and that gave inconsistent running, Check the reeds also as stated above.

Air warmed up 15 degrees and your jetting is rich?

I was wondering if it was a stator. But it idles fine and starts ok it's just down on power and power and has no hit. Jetting is a little rich but I never touched the jetting since I owned the bike and it always ran fine

Is there a chance it could be clutch related at all?

Could be, as you said there 'just' in spec so maybe their a tad worn and it's slipping?

yeah but is it possible for the clutch to be slipping the entire time?

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