'81 GS450L - Noise / do cam chain guides wear out?

[sacruickshank]

I have an '81 GS450L with ~6000 original miles. It was picked up this past winter and after the resurrection process has now been on the road for a few hundred miles.

The bike starts, idles, and runs fine, but is developing a "rattle" when riding. Usually when cruising at steady state, coasting, or decelerating ... i.e. not when accelerating.

Since the engine has been running fine, I have not (yet) taken the valve cover off not re-set the cam chain tensioner.

My guess is that the rattling is related to either the cam chain (most likely) or the clutch basket (less likely).

My question is ... do the cam chain guides on GS's deteriorate with age, even on a low mileage bike? I've had other vintage bikes where this was common, namely a Yamaha XS650, but not sure if it is common on the GS.

I've had the top end off on an earlier GS450 I've owned, so I know how to take everything apart. I just haven't because it was all working well, except for the noise.

Any thoughts from the experts?

Thanks

Steve

[Steve]

You had a "resurrection process" but did not remove the valve cover?

I would suggest you go back to square one and bring the poor bike back to life properly.

No, the chain guides do not deteriorate, either with age or miles. However, toss something loose in there and they will be destroyed rather quickly, but in normal circumstances, they last nearly forever.

[Gorminrider]

I have not (yet) taken the valve cover off not re-set the cam chain tensioner.

Why are you taking the valve cover off to "reset" the Camchain tensioner? It's an automatic tensioner. RTFM? if it is the tensioner, you might want to check and see that the lockscrew (used for removal of the tensioner)is set so the tensioner pushrod is not locked

umm tensioner blades seem to wear very well but I've seen two with cracks across the plastic on GSX400s...one of these is slightly bent so the crack is slightly open to the metal backing But I use it and my cam chain doesn't rattle. These bikes have 60000 and 72000 km...whether it's just aged plastic or the bikes have been abused by Previous owners (or me?) is unknown but a bike with a mere 9,600km? -a previous owner would be making a study of destruction to hurt it much in that period.

[sacruickshank]

Thanks for the data on your bikes, it's helpful.

To your first question, I would not take off the valve cover to check or re-set the cam chain tension. I was just stating that i had not done either of those yet. I have RTFM and disassembled the top end on a different GS450 in the past.

[sacruickshank]

You had a "resurrection process" but did not remove the valve cover?

I would suggest you go back to square one and bring the poor bike back to life properly.

No, the chain guides do not deteriorate, either with age or miles. However, toss something loose in there and they will be destroyed rather quickly, but in normal circumstances, they last nearly forever.

Thanks for the input. I did not take off the valve cover (yet) because I've lived thru scraping petrified gaskets's off 35+ year old bikes before. I did not want to do that until necessary.

[John Park]

I'd check the heat shields on the exhaust pipes, header bolts and maybe the countershaft sprocket. I doubt the source is inside the motor; maybe, but there's lots to check for rattles before you tear it down. Motor mount bolts. Bang around on things and see what you can find. The heat shields are pretty much doomed to come loose eventually.

[cowboyup3371]

Thanks for the input. I did not take off the valve cover (yet) because I've lived thru scraping petrified gaskets's off 35+ year old bikes before. I did not want to do that until necessary.

So are you saying you have NOT done a valve adjustment or even check yet? Please, go back and get that done ASAP so you KNOW where everything sits since the previous owner has no real interest in telling you the complete truth

[sacruickshank]

I haven't done the valves yet based on the relatively low mileage, under 6000 miles, and otherwise good engine performance. I'll give them a check shortly, but i doubt it's the source of the current noise.

[cowboyup3371]

Valve adjustments should be done every 4000 miles or so per the Suzuki manual. It may not be the source of your exact problem but it is a much needed maintenance item to ensure your bike remains fully operational

[Gorminrider]

yes, the valve cover gaskets can be time sink. I don't know why they need to be stuck on so tight. The black gaskets seem to be the worst while plain old karopak brown-paper work well , can be home-made from a roll and do not stick so bad-mind you, I check my valves so maybe it's just the time interval. Still, without glues and rubber base? and such the black ones have, the simpler paper ones would be easier if they do get stuck...

[sacruickshank]

I'm not sure what gasket material is on there at the moment since the bike is on loan to a friend. Getting it back this afternoon for 3-day weekend project work.

In general, the absolute easiest gaskets to work with are the black rubber gasket Honda uses on Goldwing/CX500 valve covers. I pulled some off a Goldwing that had been sitting since '95 with no problem at all. Plus they can be re-used since honda uses cover bolts that screw in enough to put pressure on the gasket but stop before they get too tight.

[Gorminrider]

Yes, the Honda gaskets are in a league of their own. I've a mere 4 bolts on my cb450's camcover so the cover itself must be extra rigid too..But they do fail eventually and can be pricey. I've never really noticed the bolts are set to not oversqueeze them! That explains the bolt's shoulder! and the rubber seals on the bolts themselves- good point!

The Suzuki cam cover is ideally torqued to a mere 72 inch/lbs., but some people wind em on pretty hard and maybe unequally too. I think the gaskets do last longer if the torque specs are followed carefully on first use. (The thicker grade of Karopak is the one to get- the thin one is not great.) If they leak, a little more torque equally on the next use can do it but they don't last like the Honda ones for sure.

[sacruickshank]

UPDATE - The rattling seems to have stopped during the last ride, but I decided to check the valves based on everyone's comments.

The good news - the valve cover came off with minimal/no damage to the gasket. I'll re-use the gasket for now and watch for leaks.

The frustrating news - The intake valves were within spec (.04 and .05) but the exhaust valves were both tight (under .03mm) and needed to be changed. Due to the randomness of shim style adjustments, the best i could get for the exhausts were .1mm. A little too loose, but better to be too loose than too tight. Plus, swapping shims back and forth might take multiple rounds to find the magical shim that was .05 thinner than the existing ones (~2.62mm) rather than the 2.55mm shims I had on hand.

[LAB3]

You should be fine with .10, don't sweat it. Here's something that mine did to me TWICE! Front sprocket nut would get properly torqued and the keeper fastened then loosen up! A newer, thicker keeper has superseded that one and took care of the problem.. It made all kinda racket that sounded like it was coming from somewhere else

[sacruickshank]

thanks. i'll check the front sprocket as well.