camchain tensioner

[IanFrancisco]

Well, my 1980 GS450 is running great, got all the charging/battery issues solved and can now run around town with the lights on without having to push start it. I have had a problem with the camchain slapping around at idle. Of course I don't hear it when the motor is above about 1500rpm, but it bugs me. I can reach down and turn the knob a little bit clockwise and hear the slapping stop but it won't stay tight. I have pulled the tensioner off twice and made sure it isn't sticking and is properly adjusted but I think the wimpy little spring behind the knob just doesn't have enough strength to do the job any more. Any ideas? The bike only has 9000 miles on it and I don't think the camchain is stretched out or the guides worn at these low miles, but of course I'm not sure as I haven't pulled the motor apart. Any suggestions would be most welcome.

Thanks, ian

[Scud]

The tensioner has a pre-load spring on it, what you need to do is take the large nut off the end of the tensioner and add a turn or two to the pre load of the spring (once you look at the large nut it will become apparent, it is half round so you can add pressure so to speak). This will apply more pressure to the tensioner and possibly get rid of the noise.

Scud

[KEITH KRAUSE]

You can also add some tension to a tired outer spring by pulling the spring end out of the hole, and winding it C-C-W one full turn and re-insert the spring end.
Also, the set screw is supposed to be backed off the rod from 1/4 to 1/2 a turn. Sometimes, the screw is at 1/4 and backing it off that extra 1/4 will allow the rod the extra clearance it may need. I wouldn't go beyond the factory recommendation though. 1/2 max. Loosen the holder nut and note how far in you turn the set screw first. If it's already out a 1/2 turn, I doubt it's the cause of the problem.
More often, it's the light spring that looses tension.

[IanFrancisco]

Thanks for the tip. I was thinking about giving that outer spring an extra turn or two but wondered if it would hold up. Last thing I want is for that spring to break, especially while riding. Don't know where I would find another one, either. How much damage can a slapping camchain do, assuming that the tensioner isn't completey useless, but just a little tired?

Thanks again.

[Anonymous]

If the cam chain is loose enough to slap, it's loose enough to skip a tooth or more on the sprocket. That's bad - no more need be said.

[KEITH KRAUSE]

Thanks for the tip. I was thinking about giving that outer spring an extra turn or two but wondered if it would hold up. Last thing I want is for that spring to break, especially while riding. Don't know where I would find another one, either. How much damage can a slapping camchain do, assuming that the tensioner isn't completey useless, but just a little tired?

Thanks again.

Like Swanny said, you don't want to see what can happen if the chain breaks or slips.
2 turns back should not be necessary. I don't think some will even go back 2 turns, mine won't. Just wind it back 1 turn.
Before winding it back, note where the hole/spring end is pointing. Such as 2:00. If the re-wind works and the tensioner is pushing the chain in more, you'll see the hole/spring end advance some. Maybe to 3:00 or so??
If it still slaps, I suppose then you could see if you can try to get another turn and re-test. But DO NOT accept the chain being loose. Service the tensioner or replace it before real damage happens. Some people buy a manual tensioner from "APE" or ?

[Poot]

I had the same thing happen to me.


TO solve it, I just used 1.5 turns of spring tension (mine had 1 coming off) and it solved the problem.


3rd times the charm!!!

[IanFrancisco]

I think I got it. Removed the 10mm nut holding the knob and wiggled it off and put 1.5 turns more tension on it. The spring cleaned up nice and isn't all corroded like I had thought.

Thanks for the input!!

[Scud]

Your welcome, glad we could help.

Scud