R1150GS Vibrations through the footpegs

[JackDaniels]

hi everyone,

i have a 2003 r1150gs with 95k on the clock, in the past couple hundred miles the footpegs have started vibrating quite badly whilst riding along, i have balanced the throttle bodies the best i can, have given it a full service and done the valve clearances.

if i pull the clutch in whilst riding along the vibrations completely disappear, im unsure now as to what it could be causing them, it has only started recently.

i took it for an mot last month and was told that my rear shock has lost all its dampning so i have a shock on order and im hoping that may fix it but just thought id see if anyone else had any ideas whilst im waiting for it to arrive.

thanks
Jack
____________________
THEORY TEST - PASSED! - 02-08-11 CBT Passed - 09-08-10 MOD 1 - 09-08-2011 - MOD 2 - 28-09-2011
2006 Yamaha JOGRR>2010 Yamaha Ybr>1995 Honda CB400 Superfour >2005 Honda hornet>1999 Suzuki Bandit 1200 > 2002 BMW R1150GS > 2013 Tiger Sport 1050 > 2007 GSXR 1000 > 2005 GS500E

[Robby]

Presumably when you pull the clutch in you're also letting the revs drop to idle. That means the gearbox and final drive aren't causing the problem, so it must be the engine or the clutch causing the vibration.

For an experiment, you can try pulling in the clutch but keeping the revs up. That will tell you if it's a problem from something rotating at a certain speed, or if it only happens when the engine is under load.

Assuming it is only happening with the engine under load, my first thought is throttle body balancing. You say you've tried to balance them, but you don't seem that confident.

[RhynoCZ]

[jaffa90]

""""EDIT: I still think it's the clutch.""
Me too.

[JackDaniels]

[JackDaniels]

[Robby]

The carbtune would be the right tool, and it sounds like you have them balanced.

For anyone saying clutch bearing, this bike runs a car-type 3 piece dry clutch. The only bearing is the release bearing, which is only in play when the clutch lever is pulled in. If the clutch was out of alignment it would be juddering when you pull away.

So it sounds like the gearbox and final drive are not an issue. The clutch is unlikely to be an issue. The throttle bodies are synchronised. The valve clearance have been done.

The vibration appears to be coming from the engine, at around 3500 rpm.

I'm out of ideas. Don't know enough about the bike. Next place I would look on any bike would be engine mounts. With rubber mounts I'm looking for a collapsed one allowing it to transmit vibration, with solid ones I'm looking for loose bolts allowing it to amplify vibration at certain harmonics.