GS550 Engine noise during idle

[csgoh]

Hi all, my 1981 GS550T was running perfectly until this morning when a loud constant grinding noise from the engine whenever I go into idle. Some observations
1. Idle - grinding sound
2. Idle - pull in clutch . Still grinding sound
3. First gear clutch pull in - totally no grinding sound
4. Riding along in with clutch release - grinding sound. Maybe less but I believe it's due to the rpm drive drowning compared to idle.
5. Sounds like the noise is coming from the transmission area of the engine.
6. Shifting is fine and no clutch slipping.


Recent maintenance I did:
1. Replace clutch steel plates as some of them were warped beyond tolerance as per manual.
2. Valve clearance
3. Engine oil and filter change
4. Been opening and closing the clutch cover (right side) a few times past week as it was leaking and I was changing gaskets and replacing them as it was leaking even with new gasket.

Can listen to the sound here:

Checks I have done:
1. Opened up the clutch cover and checked the spring bolts as well as the needle bearing behind and the huge nut behind that. All is tight and well.
2. Readjusted the clutch push rod from left side to sit and then 1/4 turn out
3. Started the bike after the above and realized that when it's cold, the sound is not there as I don't believe the checks I did above changed anything other than letting the bike cool down. Haven't brought it out to warm up the engine though.

Really appreciate any tips or help and where should I look at.
Issue is also over at where I am (Malaysia), some parts are not so easily available so purchases have to be pretty accurate as in when I buy from ebay shipping from the states costs a bomb and buying the wrong parts is costly.


Some pics of the bike since I recently gave it a makeover and I know everyone loves pics:

[steve murdoch]

Welcome to the site, csgoh.

Can't help with the clutch racket but the bike looks great.
Love the dual disc, black rim spoke wheels. A clean cafe custom.

[rphillips]

"Grinding" noises rare on a GS. Only ones I remember from a GS was either the clutch basket, big nut loose, or the starter clutch. GS starter clutch bolts are kind'f known for working loose.

[csgoh]

Thanks. I just got in there again and removed the nut and checked the springs on the basket. Tighten everything up but it's a b### to get the big nut torque to spec without something to hold down the basket from turning.

Will test tomorrow and get into the starter clutch if still not recified

[tom203]

Nice looking bike! Can’t help with noise but since you said this…

“Been opening and closing the clutch cover (right side) a few times past week as it was leaking and I was changing gaskets and replacing them as it was leaking even with new gasket“
Make sure you got cover screws in right spot….easy to mix up and prevent cover from tightening down. Review their positions

https://www.partsoutlaw.com/oemparts/a/suz/50d3f8bef8700230d8b4cfb9/crankcase-cover

[Rijko]

Thanks. I just got in there again and removed the nut and checked the springs on the basket. Tighten everything up but it's a b### to get the big nut torque to spec without something to hold down the basket from turning.

Put the bike in 1st gear, foot on rear brake pedal.. easy that way.

[Rijko]

s-l300.jpg

Or make your own tool.
Still have the steel clutch plates
you replaced ? Those are perfect
for a tool like that.

[csgoh]

Out of curiosity, would noises caused by me clumsily dropped s nut into the cavity where the starter motor is.

[rphillips]

No, no moving parts in the cavity where where the starter is.

[csgoh]

An update, after last night's clutch basket spring stretching as guided by basscliff and tightening of the clutch basket nut. Seems the grinding noise is gone but I haven't had a chance to do a proper long ride to be sure though. Will keep this thread updated on the progress for others with same issues.\

Further update: thus far all is good and the sound is not back. Have no idea what i did. Maybe backing the clutch adjuster rod (the adjustment on the left side of the bike) helps. Im suspecting it could be that. Maybe its the washer between the needle roller bearing at the tip of the clutch push rod worn not evenly causing friction sound when its not pushed on the clutch plate.