cam chain stretched?

[pfoster99]

Hello folks, I'm new to this forum and appreciate any helpful information. I have an 83 suzuki gs650g, (the shaft drive, plain bearing crank) and I believe I may have a stretched cam chain, but I'm not dead sure. The bike has about 48k on it and runs strong, has the classic gs cam end float rattle at idle that I'm not worried about, but I was out for a ride the other day and apparently my cam chain tensioner malfunctioned- chain started rattling like crazy. PUSHED the bike home, pulled the seat, tank, then carbs and then the chain tensioner itself. I noticed the set screw was way tight (not sure why it started rattling so suddenly) but I pulled it apart, cleaned and lubed it up, and set it back in. I then pulled the valve cover, checked the chain for tension (checked valve clearance while I was at it-all good) and everything appeared fine. Put everything back together and she fired right up and no rattle- BUT I am definately hearing a constant 'chain' noise-that was atleast much less prominent than before. The best I could describe the sound is that of rain - I am wondering if, when the tensioner failed, the chain was stretched, or is it normal to hear the chain on these old bikes? I do not have the tools to check the chain- unless there is another way to check it? (Without using the special tool?) Or shall I go ahead and replace it? A new tsubaki? Chain only runs around $50... which doesn't seems bad, because I am imagining my cam timing to be in better shape with a new chain installed... especially on an almost 50k motor with I guess is the original chain..... any help is greatly GREATLY appreciated. Thank you much.

[rapidray]

I doubt SERIOUSLY the chain is stretched enough to need replacement. The factory SUZUKI manual will have a specific pin count # on the cam chain for you to measure & the maximum allowable stretch. I would start there to eliminate the chain as the issue. Ray.

[TheCafeKid]

Yeah I agree with Ray. While I've not been inside nearly the amount of engines he has, I've been in more than a few and never once have seen one with a cam chain anywhere close to out of spec.
Heck even the GK I had for a bit had over 100K miles on it and it was still well within spec.

[pfoster99]

Thanks ray- but like I Said, I don't have the means to measure the chain- unless someone knows where I can get the necessary tools? and I guess I should have added that the motor still runs great, and that the sound isn't altogether LOUD... its just more noticeable than before. (Possibly having something to do with the tension now being correct?)so I guess my question should have been, should I be able to hear it at all? Or is a little chain noise normal and benign? Id rather not dig into it again, but unfortunately I've never SEEN another gs650g, let alone had the chance to hear it run...

[pfoster99]

Thanks guys- I feel more comfortable with it now....especially considering a 100k. Motor that is still within spec..(toyota 22re xD) I keep fresh oil, check the valve clearances often, so for now I suppose ill keep it going. I think it probably got around 15-20k left before the crank is about finished anyway.. I know the 650s aren't quite as tough. Maybe I'm just paranoid lol.

[TheCafeKid]

Thanks guys- I feel more comfortable with it now....especially considering a 100k. Motor that is still within spec..(toyota 22re xD) I keep fresh oil, check the valve clearances often, so for now I suppose ill keep it going. I think it probably got around 15-20k left before the crank is about finished anyway.. I know the 650s aren't quite as tough. Maybe I'm just paranoid lol.

Ride more, worry less

As long as you keep your regular maintenance up, and fresh oil in her religiously, there's no reason she won't pile up the mileage.

The noise you hear, does it go away when you apply throttle or get louder? Many of the 8v models would develop a chatter or rustling sound in the top end from cam end "walk". This far no one seems to have had it cause any apparent damage or bad running, just a little rustling. It goes away once you apply throttle and the tension on the chain tightens up.

Have you recently adjusted your valve clearances? Sometimes people hear the clicky clack in the head after adjusting tight valves that wouldn't have made as much noise before also. If she's running well, don't fret. Just ride her

[tom203]

Make sure you understand how tensioner works-with tensioner out of engine, you push plunger back into its housing, lock it with setscrew (not lock nut), install into engine and then release the set screw (this lets plunger slide into chain); finally, you tighten lock nut to prevent setscrew from moving (and interfering with plunger).
Since your tensioner got too loose running, it's possible camchain jumped slightly on camshafts- best to remove valve cover again and check camshaft timing,not how tight chain looks.
I don't think chain stretched, more likely the wiper that bears against chain has worn at 48k.