Take it from me get rid of it chalenger 770 clutch cam chane top end got it back burned oil bad it was a 18 motors a hisun made in China bought ayamaha wolverine
Mines got hisun motor cub cadet chalenger 750 just a junk motor lots of trouble every since new it started burning oil at 1500 mi new head timing chain before that
I hear you I've got an 18 its motor is junk I've heard that some other brand motors may fit with a little work mine burns oil with 1500 miles had same prob with timing chain valves
Yes I did new muffler and pipes it broke offset the manifold they didn't replace it so I welded it with two straps for reinforcement didnt get 500 hundred miles out of the new one
Put strap in front and rear of manifold it is holding up so far any other problems with motor I've had a lot wish it was good enough to trade in even if it cost 2000 dollars