By
97kingquad
I have been rebuilding some ATVs in my spare time and teaching myself along with the help from the internet how an engine works and getting bikes running again is quite enjoyable. I even built an arctic cat 300 4x4 from two parts bikes the had seized motors and missing parts. It was pretty enjoyable.
So I am now working on a sazuki quadrunner 300 1992 which had a whole list of issues when I got it. I have fixed almost everything I need to in order to get this bike running. But something is going on inside the head or crankcase.
I had to replace the timing chain because it was very stretched due to the previous owner.
What the issue was, the timing chain was off the sprocket inside the engine due to it being stretched it slipped off. So the previous owner rebuilt the top end thinking it would fix it which it may have temporarily, but when doing so they welded an extra inch onto the tensioner to hold the chain tight. Which as you can imagine caused a dozen other issues.
So that stretched the chain to the point where I could remove the cam with the tensioner in.
It beat the sliders all to hell. Destroyed the cylinder housing and obviously ruined the tensioner.
I didn't realise all of this until after I rebuilt the engine. I noticed wear where the timing chain runs through the cylinder. I found the cam had no retaining chair, or clip whatever you want to call it so the cam was beat to sh** also. It had almost an inch of play side to side.
So I pulled the head off of my parts bike and fixed all of it. Then put it together and went to pull it over and found it was not on the sprocket (this is when I realised that all that damage and the welded tensioner was because the timing chain had been off the sprocket)
So I pulled the stator cover off and pulled the flywheel (which I should add to get at the stator cover I have to remove the rear tire and a arm as well as remove the bolt through the front of the engine. And the exhaust system has to be removed to pull the cylinder as the exhaust guard is bolted to the side of the timing chain tensioner. Stupid setup. Glad the king quad doesn't have that.
So I got everything apart and the flywheel off. New timing chain (nice and tight now) put the head back together and flywheel but it is quite hard to turn the engine over. I can but with difficulty. When the valve cover was off it seemed to spin much more freely. Before I tear everything back apart and start again any ideas on what it is?
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