Finally got around to rebuilding this beast. I have a couple questions tho. My current piston is marked II-B, and my new one is marked I-B. What are the differences and do I need to return these for the other type?

Also, the manual states the arrow should face the rear of the engine. This one was facing toward the front. Could that have caused the wear on the middle ring? It is pretty considerable.

Going to check out a 2018 zforce 1000 this weekend. 1900 miles. What should I watch for on these ones?

Hi all, just did some testing on my 2015 800EX. Have a lot of oil in the air box. Compression on cylinder 1 was about 60psi, cylinder 2 was 120psi. So got a leak down tester. At 90 psi I can't build more than 20psi in either cylinder. I can hear air escaping, but can't find it. No bubbles in radiator, used a stethoscope to try to locate the culprit area, but I just could not find anything.

Motor starts and runs fine. No power issues, goes good. I have been up to 60mph with it and ran out of room before running out of throttle. Looking for any help I can get on this, because I am stumped at this point.

I bought this thing for cheap money last week. Prior owner was going to trade it in but dealer said it needed top end rebuild due to exhaust smoke. I have not seen any smoke. It does get quite a bit of oil in the airbox quickly, so I assume this is what they were talking about.

How hard are these things to rebuild? I am mechanically inclined, but don't want to fight with it if I need a bunch of special tools and such. For the price I gave, I can pay the shop to do it and still be happy with the investment. But it's always nice to DIY and put that labor $$ towards other toys!



Chris