Bought this sled in July been going over it since. Before I bought the sled I did a compression test. I bought my compression tester at Crapy Tire so I don't exactly trust it.
The test read about 120psi each side (throttle closed), I don't remember the exact readings, but it was in that ball park(115-120). The sled has 6k km on it so I was expecting low compression anyways. The guy I bought it from said he had done a top end before the previous season, but I figured he was lying, he couldn't even give me an answer on what pistons he put in it. I named all the popular manufacturers off the top of my head, but he couldn't decide lol.
So I got the sled and I've been going over it, so far I've cleaned the carbs(people recommended I shim the needles 0.20 to solve the midrange lean issue, so i did), cleaned the R.A.V.E. valves, replaced and repacked the PTO crank seal and some other little things. I haven't gotten around to diagnosing the top end more thoroughly So I figured I would, even though I was sure it needed a rebuild anyway.
I have done some research on compression tests, some people say to compare hot to cold psi and I've also read people saying about to have the throttle open and some say to leave it closed. A quick word about "hot" compression, I let the sled run for about 3min. I would have liked to let it run longer, but I only have time to work on my sleds after 9ish so didn't want to "edit for bad language" off my neighbors.
*I attached a picture of the results*
So I think its pretty clear I need a top end rebuild. I think I'm going to go with the MCB Dual ring pistons, I have read a bunch of people recommend them.
Should I hone my cylinders? Is there any issues to look out for on these engines?
Any input is appreciated