Update on 1999 220 bayou that i bought

In a earlier post, i was on the fence about buying a 220 that didnt run correctly. Well, i bought it and tore into it a bit and found the cam chain tensioner stuck and the chain was loose. I got the tensioner working correctly according to the manual but the bike still doesn,t run right. I think the timming is set correcly but the upper timing mark description is a little fuzzy in my repair manual. the dot on the cam gear is aligned to the top of the head were there is a raised spot on the casting which is about 12 o"clock. my question is if the chain was loose is that enought slop to allow the piston to hit the valves. The bike runs but no power. if you throttle it up it like it wants to but cant, real loud out the carb. tomorrrow i am going to check the valve adjustment. also, if anyone can answer this one, the book shows only one roller bearing on the cam, but on line they show two. which is correct.. the bearing on the chain side has alot of play without the tensioner on well i will quit now and wait for any answers.