Knocking noise when idling (GSA 07)

[motorbaker]

On my 07 GSA, now a few miles short of 12k, I'm noticing a loud knocking noise coming from the area at the front of the shaft drive (near the engine) when idling. Doesn't sound healthy, like something is loose and banging around. It's not a regular pattern but is on/off all the time and makes the bike shake. Sounds a bit like a machine gun in short bursts. Any idea what this might be?

MotorB

 

[GSmonkey]

Front of shaft drive = gearbox. Is it still there when you pull the clutch in?

Could also be something simple like throttle bodies needing balancing - it can run like a dog and shake/vibrate if they're out of sync. Has it been serviced recently?

 

[Richard M]

Time to head to the Dealer to get it checked out. (Maybe for a slightly early service) If you get the ‘this is a characteristic’ comment , insist on borrowing one of their GSAs and learn to do burn-outs and donuts

 

[Fenrir]

Sounds a bit like a problem I had with my bike I would get a Knocking sound as if the big end was about to give out. The knocking would stop when the engine was warm this problem was traced to the cam chain tensioner sticking in and releasing when the oil starts to get warm this is a known problem with BMW and commonly occurs if the bike has not been used for any lenth of time. If this sounds like your problem then don't worry to much if this happends from time to time if the problem persists then get the tensioner replaced I'm told this is not a difficult job? You my also try turning the engine over every week if the bike is to be stood still for any lenth of time this sould stop the tensioner from sticking in. Hope this helps.

 

[cookie]

poorly made remus Y piece touching the gearbox?

 

[motorbaker]

It's about to have its 12k service, but I'd like to have as much info as possible before going in, in case I get the usual "oh that's standard on all bikes guv, nothing we can do..." response!

I've had the Metal Mule exhaust put on but I don't think that's the problem.

I forgot to mention that the noise starts when I put it on the centre stand and put it into 1st gear, idling. Yes, when I pull the clutch the noise disappears. As I mentioned here and in other threads, the throttle is extremely jerky (especially noticeable below 50mph) to the extent that I have to use the clutch to get round a roundabout smoothly and the only way to ride smoothly in traffic is to freewheel as much as possible.

Any further thoughts?

motorBAKER

 

[Kenny Rodkiss]

You don't want to be running in gear on the centre stand as the drive shaft angles are too acute.
You are hearing the drive shaft trying to tie its self in a knot.

 

[motorbaker]

You don't want to be running in gear on the centre stand as the drive shaft angles are too acute. You are hearing the drive shaft trying to tie its self in a knot

Ok, just tried it on the road at slow speed - idle throttle in 1st, 2nd and 3rd gear: same noise, same sensation. Bike jerks along in spasms.

mb

 

[seanred]

You don't want to be running in gear on the centre stand as the drive shaft angles are too cute.

Too cute for what?

 

[GSmonkey]

...the noise starts when I put it on the centre stand and put it into 1st gear, idling.

This is quite normal, what you're hearing is the backlash in the gears. There shouldn't be a noise when you're driving as all the slack is taken up.

The bike will be jerky though at idle with the clutch out in first even when driving along, especially if its due a service and the TB's are out of balance. It does sound normal, unless its a real nasty noise.

 

[motorbaker]

The bike will be jerky though at idle with the clutch out in first even when driving along, especially if its due a service and the TB's are out of balance. It does sound normal, unless its a real nasty noise.

Time to head to the Dealer to get it checked out. (Maybe for a slightly early service)

Thanks for your help. Got it booked in for an early service on Thursday. I'll mention the problem and the Throttle Bodies etc, and see what happens.

MB