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Plastic bits in oil plug

Ruff

Member
Joined
Jul 23, 2020
Total Posts
27
Total likes
1
Location
Sycamore, Ga. USA
Hello all, haven't visited the site in quite a while. Just changed the oil in the CB450 and have plastic bits in the oil drain plug. I'm thinking it is from the cam chain roller/guides. As far as I know that's the only place it could have come from. Bad time for this getting near spring.
 
Squarish and crumbly are probably the remnants of the cam chain damper rings on the cams, nothing to worry about there. Other irregular bits of black rubber/plastic could be cam chain tensioner roller, the others in the typical 450 engine don't get enough abuse to ever shred, at least in my experience. If it's only the tensioner roller it can be repaired without pulling the engine and you could remove the tensioner to inspect it and/or replace it as long as you follow the proper steps.
 
Thanks Ancientdad, As soon as I have time, I'll inspect the tensioner. I'll do a little research on the proper steps. Any tips are appreciated. I do have an old engine from a junkyard that may have a good tensioner in it or maybe look online for some old/new stock. Thanks for the info.
 
Thanks Ancientdad, As soon as I have time, I'll inspect the tensioner. I'll do a little research on the proper steps. Any tips are appreciated. I do have an old engine from a junkyard that may have a good tensioner in it or maybe look online for some old/new stock. Thanks for the info.

The most important aspect of checking or replacing the tensioner is to turn the engine over (valve covers off) until you see both intake valves are closed, then do NOT turn the engine after removing the tensioner assembly. With an older, used cam chain there will be a fair amount of slack once the tensioner is removed from the back of the cylinders so if you did try to rotate the engine it could jump a tooth at the crankshaft and change the cam timing. It's easier to have the carbs off as well, so plan to do the valve and cam chain adjustments while you're there too (but after you finish the tensioner work, of course). One more thing - be sure to push the "new" tensioner all the way back before installing, then adjust.
 
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