1981 GS650GLX - Engine Knock

[Anonymous]

I recently purchased a 1981 GS650GLX and noticed this after the first few rides. After riding a few miles with the engine warmed up, at idle, there is a distinct engine knock occuring about once per second (very rythmical, once every second). If I increase the rpm's over 1500 or so, it seems to disappear (could just be that it is harder to detect with increased engine noise). It appears to be coming from the upper-front of the engine when I stick a screwdriver from my ear to the engine. When the bike is cold (after first starting) the knock is not apparent. The bike appears to run fine and there are no performance problems that I can see.
I have read a few articles about cam end float on this site which is a possibility. Before I diagnose it as that, does anyone have any other thoughts? Could the timing(cam) chain need tightening(adjustment)?
Thanks in advance for any replies.

[Anonymous]

The only thing I can suggest is that it could be the springs in the clutch basket. This happens when you are reving around the 3500 to 4000 rpm range. I understand this is fairly common through most Suzuki GS models I have it and so do a couple of other GS owners I know with the GS 800 and GS1100. I can't say I have heard it at idle though.

Colin

[Anonymous]

Does the knock disappear after awhile? My old 1000 had the Cam float symptom, and it was only when not cold, but not completely warmed up. Annoying sound, almost embarrassing. But it went away after awhile.


Tim

[Anonymous]

It only knocks after it is warmed up. (after driving for 5-10 min, I guess I would call the engine hot). The knock appears only to occur at idle and it does not go away. It certainly sounds like it is coming from the upper-front of the engine.

[Anonymous]

Sounds like cam end float without a doubt.
Wrong area for clutch rattle, wrong kind of noise for cam chain.

Ignore it, its harmless.

[Anonymous]

How can you say its harmless? Shame on you!! I personally have stressed myself out listening to various noises that seem to come and go with the seasons, time of day and that sort of thing. Suzi is my baby ya know?

[Anonymous]

I know what you mean. I posted the following a while ago. I'm still listening to that damn noise every day!! 8O Somebody please reassure me!!!

"Can anyone whose fitted one of these kits answer this question? Thanks in advance.

I have noticed that after fitting a Wiseco 1085 kit there is an increase in piston noise from the engine. This noise is quite high pitched and sound a little like a loose small end bearing, and occurs at moderate to large throttle settings. It decreases when the engine is warmed. It isn't detonation and there is no appreciable wear in the engine. I have used the same pistons in 2 different engines, 2 different blocks etc. with the same noise
I think the noise is either some piston rock, or just a characteristic combustion noise due to the increase in c.r. and I just live with it, but can anyone else confirm that this is normal with a Wiseco kitted GS1000? "

[Anonymous]

This noise is a typical GS noise. It's coming from the camshafts. Suzuki engineers haven't done a very good job here. But it's harmless. I've got two GS850's and a GS550E, they all make this noise for years now, and they still run like hell.
Enjoy it, it comes with the GS for free!!

Jojo

[Anonymous]

same sound on my bike

Glad I checked out this thread. My 1982 GS650L does the exact same thing. Annoying knocking sound after the engine heats up. Really only notice it when I am stopped at a traffic signal.

[Anonymous]

Thanks for all replies. Until something else occurs that would lead me in another direction, I am content diagnosing the problem as the "cam end float". I will however check to make sure the cam chain tensioner is working properly.

[TheNose]

My '77 GS750 does the same thing. It is intermittant though. I usually hear it when it is warming up, but not always. I too will assume it is harmless, but it still makes me a bit uneasy.

[Anonymous]

Noise

Are you sure the noise is from the Engine?

When I first got my bike on the road, I heard a similar noise while riding and thought cams ..... I mistook Chain Slap for engine noise. :?

I have since learned to tell the difference

I throw this out for your consideration. You never know when it might be something simple.

Good luck

[Anonymous]

It's a shaft drive, and it only occurs at idle. Unless you mean cam chain which is something I thought of earlier.

[TheNose]

Mine only makes the noise while at idle. As I said before, it doesn't always do it either. I will be concerned about it until I get confidence in the bike, but I think (hope) it is the cam slop.

Terry

[Anonymous]

cam end float

wow , finally diagnosed my noise also.
thanks !! but can you shim it ?? its really a disturbing sound !

gs650gm * and loving it