Did this bike manage to hit it's power band before doing your 'top end'
rebuild &/or replacing it's Xhaust?
Remembering of course that two strokes live or die by their Xhausts and squish band ....
I would suggest reverting back to the original Xhaust first
, (as the new one may well require re-jetting
), and if that fails to remedy the prob. ... then check head gasket thickness, (I'm assuming you didn't re-use the old one
?), and then check your piston to head clearances, as this is ultimatly your squish band.
... and then there's the ol' favourite ... Who did your rebuild? (did they maybe break a ring on installation
), and ... was a new piston and / or rings involved in this 'top end'
Wrt oil and the Xhaust ... It's a two smoke
... It burns and leaks oil!
... deal with it or get an underpowered 4 stroke