MOTO1988 348cc Engine 83mm Cylinder Piston Ring Top End Rebuild Kit For YAMAHA Warrior 350 Raptor 350 Grizzly 350 Big Bear 350 Bruin 350 Wolverine 350 Moto 4 1987-2011 (black)

I checked ring gap and they were in perfect tolerances. Nice cross-hatching inside. The compression ring didnt appear to have a mark on it showing which side was up, but after holding at a certain angle in the light a was able to barely see it.Currently in break-in period for a 1998 yamaha big bear 350. Only thing I didn't like was they did not provide the quarter sized o-ring that goes in the oil channel between this cylinder and the case. If you are that far into it, you shoukd replace that o-ring. Also, I would not use this manual tensioner, keep the stock auto tensioner if it still works. Happy with this so far, and you can't beat the price.

This fit nicely for a 1995 Yamaha Moto-4 350 but required more gaskets to do the job which were not included in the kit. I bought another complete gasket kit that had valve seals (highly recommended changing these when you do the top end). The complete gasket kit with this cylinder kit did the job. I recommend putting some yamabond 4 on the base gasket. Once installed I had 135 psi from my harbor freight compression tester and the machine runs great. I would buy again.

Was holding off to thoroughly test before making a review. I installed this top end kit one evening, pretty simple install. Was just curious about the quality of the machine work, so I double checked the flatness of the head mating surface, bore size and egg shaping/tapering. Also checked piston size. All were within spec, and honestly, a little more precise than expected. Rings seen to be pre-gapped. Install was smooth, and after a short break in time I started ridding hard(as I always do). I’ve put about 20hours on these parts and they are performing just as well as the day installed. Highly recommend. Take your time on the install, as cleanliness and proper install/assembly will make a worlds worth of difference as far as longevity.

The cylinder wall has nicks and small indentions. Poor quality. Sold as “new”.