How can I tell if my cam chain is too loose ?

Faster675 · May 29, 2011

I've read "all" the threads on CCT and Manual CCT.

... my bike is an '06, with 24k HARD miles on her.

After a weekend of two days on the track .... a couple days of riding later, I heard a noise on the way to work which sounded "clearly to me" like a loose cam chain (on accel and decel, not at idle) ... so I got her towed home.

I have taken off the crank cover, and it "LOOKS LIKE" the Cam chain is plenty tight (both before and after rotating the engine several times).

... in addition, I see no evidence of the "case grinding" which others have seen.

Other than replacing the stock tensioner with the race kit tensioner (which I already have) and having the noise "go away", how do know if my cam chain tensioner is functioning incorrectly and allowing too much slack in my cam chain ? Like I said, it looks plenty tight ... how can I tell if it is too loose ?

Tonymac · May 29, 2011

Did you check your main chain?

mikereiser · May 29, 2011

If i were you i would just re adjust the cct and see if that fixes the problem. Might not be a bad idea to change the chain, depending on how hard you are on the motor, although that chain should last 50k+

MacBandit · May 29, 2011

50k if you are just easy touring. Most of the ones I replace (frequently) at work have 30-40k. The amount of force that's applied on these chains due to the aggressiveness of the cams is pretty stressing and the chains wear out fairly quickly. The chains are getting lighter and lighter as well as manufacturers are trying to find ways to reduce rotating mass.

Faster675 · Jun 13, 2011

Replaced with Race CCT ... everything seems fine now. No more loud "grindy" noises (except for normal Triumph grindy noises), bike runs like normal now. :cool2:

Measured (half length) Cam Chain according to manual, (and checked for any odd wear patterns), cam chain appears fine, but will still replace at 24K valve adjust.

Before replacing CCT, it did make a very nasty noise (that's why I got her towed home), seems like stock CCT was tight enough at low RPMs (didn't make funky noises), but above 3K rpms, stock CCT would loosen and allow a bunch of slack (nasty loud grindy noises) at higher revs.

The part of the engine case that sticks out above the chain (near front of bike) did show a small amount of the "tell-tale" loose chain wear marks. When I changed the oil, I strained it through cloth and saw a little bit of evidence of tiny aluminum particles (sub micron ? )

Power-Tripp · Jun 13, 2011

It is the DiD cam chains that seem to stretch more than others. These were used on the early D675s. If you hear the dreaded cam chain rattle at idle - do not ride the bike. the cams can jump timing, and the chain will eat into the sprockets and block spreading metal into the oil system.

The tensioners can work just fine at lower rpm, but the ratcheting paw can drop back a few teeth under decel at higher rpm. Eventually this can cause the paw to jam by locking at an slight angle in the tensioner.

On our shop 675s, we replace the tensioners with APE units and ride on. If you are tracking the 675, I highly suggest you do the same.

Faster675 · Jun 22, 2011

The teeth on the paw were visibly worn ... which would indicate that the original tensioner was not holding tension at higher rpms ... thus the "gnarly" grinding noise above 3krpm ..

Put on the race tensioner an all is good :nod:

How can I tell if my cam chain is too loose ?

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