Bike runs good when cold but loses power hotter the engine gets . Replaced piston ring , piston and old ring looked good every thing else in top end was ok . Need suggestions on possible causes .
maybe you need to run a little premix, or switch of the autolube altogether, and go to full premix - my guess is you are not getting enough two stroke through ?
DS-80 = JR80 - cool little two strokes for beginners