XT550 cam chain tensioner

Can anybody tell me how the ACCT of the older model XT's work? I know some older Hondas had a bolt and oil pressure design, but I'd like to know if they are the same or if they use a diff design. Thanks a bunch.

I pulled one apart, and all there seems to be is a spring which puts a certain amount of pressure on the adjuster, and a little locking device which stops the adjuster from backing out (well supposed to, my dad found out what happens when it backs out, long story short, bent valves). I think the spring is what regulates how much the chain is adjusted.

Sounds like my incident that I had. My dad thought he knew how it worked, and he removed the bolt and almost lost the spring inside. Mine still had a lot of springiness(sp?) in it, but I have this really loud ticking sound coming from the chain. Even if I cruise at 70mph, I can hear it above the exhaust and the wind noise. Really starting to worry me...it can't be valves as I adjusted them a week ago. I'm stumped, but maybe it's the chain stretched too much

Did the sound start only after you opened the tensioner device? If it was before, is the noise more or less than before?

The tensioner is a ratcheted spring that pushes the chain guide along the side of the chain and takes up any slack. Doesn't require any maintenance, but on these old bikes the spring will eventually lose tension. You'll know it when you see that the cam chain tensioner is fully extended when you remove it. I once used some washers placed along the spring guide to shim up an old spring and it worked fine... for awhile.

I have a little over 10k miles on my 82 XT550. When I had the engine apart for another project, I noticed that the chamber where the cam chain runs showed areas of wear which were caused by the cam chain rubbing along the sides of the cylinder. The chain was loose enough to slap along the sides and wear grooves there, even when the tensioner was maxed out. So, time for a new cam chain! Instead of going with a used EBay chain, I replaced it with a brand new one since it is a much better choice in the long run.

I think that any noise you hear from the left side of the cylinder area can be attributed to the cam chain system. That, or maybe the flywheel.


Did the sound start only after you opened the tensioner device? If it was before, is the noise more or less than before?

The sound was there before I opened it, but I'm 99% sure it's gotten louder ever since. I **suppose** you could take the camchain off an XT600 and fit it to the 550, since the engines are almost identical except for the XT550 having an iron liner as opposed to the Plated one of the 600. Oh, and of course the 3mm bigger bore. I'm thinking of replacing the chain anyways, as I think it's stretched beyond what the ACCT can mend.

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