Loose marbles noise in GS 1000 engine

[John Kat]

I restored a GS 1000 EC with a complete overhaul of the cylinder head ( valves, guides...) and installed new piston rings on the existing pistons.
The bike is running fine with lots of power but at idle of just off idle it makes this unpleasant noise as if you were shaking a tin with loose marbles inside
FYI, the clutch basket was changed as well...
I see two possibilities:
1) the pistons are too loose in the cylinders
2) there is a bearing somewhere that rattles.
Any experience out there with the same symptoms?

[Agemax]

rattly cam chain?

[hampshirehog]

Unlikley to be either I would suggest. There's a long list of what it could be but starting somewhere:

Did you tighten the cam caps? Are they the original caps?
Cam chain adjuster fitted and working properly?
Cam chain guide fitted and the right way round?
Valve clearance ok - and not one that's wildly off?

[elrico]

Is Gs gas tank installed and all parts/ componets assembled,like as a complete machine close to road test or GS in shop using aux.fuel container ,still being sorted out?

[steve murdoch]

My first thought was a clutch racket but i see you changed that.
Was it new plates, springs? Properly adjusted?
Does it make the same noise when in gear?

[John Kat]

Unlikley to be either I would suggest. There's a long list of what it could be but starting somewhere:

Did you tighten the cam caps? Are they the original caps?
Cam chain adjuster fitted and working properly?
Cam chain guide fitted and the right way round?
Valve clearance ok - and not one that's wildly off?

Valve clearance checked after 1000 km.
Cam caps are tight and showed minimal wear.
The cylinder head makes almost no noise.
I didn't change the cam chain but it was still within spec.
What do you mean by fitting the cam chain guide the right way around?
Is it the one between the camshafts with an arrow on it?

I had another idea: could it be the starter one way clutch?

[John Kat]

Is Gs gas tank installed and all parts/ componets assembled,like as a complete machine close to road test or GS in shop using aux.fuel container ,still being sorted out?

The bike is fully assembled and I've done more than 1000 km with it.
The valve clearance is fine.
There is no noise from the cylinder head.

[Agemax]

Valve clearance checked after 1000 km.
Cam caps are tight and showed minimal wear.
The cylinder head makes almost no noise.
I didn't change the cam chain but it was still within spec.
What do you mean by fitting the cam chain guide the right way around?
Is it the one between the camshafts with an arrow on it?

I had another idea: could it be the starter one way clutch?

could be a loose starter clutch but then it would struggle to turn the engine over, or maybe its a badly worn starter clutch

[John Kat]

could be a loose starter clutch but then it would struggle to turn the engine over, or maybe its a badly worn starter clutch

Maybe so, as when I start the engine it doesn't make the same noise as my other GS's.
Do you believe I could pull the starter motor out to confirm the diagnostic?
Of course, I would have to push start the bike ( wish me luck!).

[hampshirehog]

I thought you had just rebuilt the motor and it was making the noise straightaway but I see now you have a 1000kms on it - so ignore what I suggested earlier, other than is the cam chain tensioner working ok.

Yes, the starter clutch is another candidate - usually loose bolts or shot springs. Just pulling the starter motor doesn't affect the starter clutch - if you bumpstart it then you'll still have a loose starter clutch. You have to pull off the stator cover and 'go in' from there.

If the noise is a 'clackety clack' it points very strongly to the starter clutch.

[John Kat]

I thought you had just rebuilt the motor and it was making the noise straightaway but I see now you have a 1000kms on it - so ignore what I suggested earlier, other than is the cam chain tensioner working ok.

Yes, the starter clutch is another candidate - usually loose bolts or shot springs. Just pulling the starter motor doesn't affect the starter clutch - if you bumpstart it then you'll still have a loose starter clutch. You have to pull off the stator cover and 'go in' from there.

If the noise is a 'clackety clack' it points very strongly to the starter clutch.

No fun as you need a special tool to pull the flywheel off first and then if it is the starter clutch, I saw the price on CMSNL.COM...over 180 Euros!

[Agemax]

if the main rotor bolt has come loose, and the flywheel/starter clutch has come loose then the rotor will pop right off by hand.
happened to my gs. i lapped the rotor onto the crank with some fine valve grinding paste, then cleaned it up, tiny bit of bearing fit on the crank then refit the rotor and locktite and torque the mounting bolt up.
no problems since then

[hampshirehog]

No fun as you need a special tool to pull the flywheel off first and then if it is the starter clutch, I saw the price on CMSNL.COM...over 180 Euros!

Or £30 here for the repair kit:

http://www.wemoto.com/bikes/Suzuki/GS_1000_EC_EN_SN_Chain_Drive/78-80/picture/Starter_Clutch_Repair_Kit/

I lent my puller out and never got it back otherwise you could have borrowed it for the p&p. Somebody else on here will have one (but they're not too dear anyway)

[elrico]

Engine , drive chain front sprocket loose,engine mount brackets:tin/ stamped/steel covers loose,sorry not very familiar with your GS model,if clutch cable actuated ,alum adjustment.cover if loose really a rattler. You hear sound:If bike engine running,idle in neutral,blip throttle quiet down or engine running ,in gear,clutch is in or out..? Sound harmonics elusive to pinpoint,some ideas/checks may seem "lame",but you are on search for resolve.no stone unturned.

[John Kat]

Thank you guys.
I will open the alternator cover this W.E. as it's still the easiest path forward.
I'll keep you informed about any progress.
I will also open another thread for another GS 1000 engine that annoys me with valve clatter noise only when I ride the bike
Lot's of fun these old GS machines