1997 R1150gs.. Transmission or drive shaft jolts after gearing down

[Quicktoys2]

Hello,
New here from Greece and asking for a friend... His 1997 GS1150 with 90000km has a jolt (knock) after gearing down and then apply gas (accelerating) . Not noticed when gearing up.
He has taken the transmission apart and all the gears and parts seem to be in good condition. Has anyone had this issue and if so what should he be looking at?
Thanks in advance.

 

[theoneandonly]

diagnosis is everything .

 

[Davey B]

Not that it should make much difference, but did they make an 1150 in 1997? Is it a later 1150 or a 97 1100 ?

 

[Quicktoys2]

Not that it should make much difference, but did they make an 1150 in 1997? Is it a later 1150 or a 97 1100 ?

You right it's a 1100 and NOT a 1150..... Still trying to figure out how to edit the title.

 

[squibb34]

My initial thought was the driveshaft UJs ......... https://www.realoem.com/bmw/enUS/sh...9E-BMW-R_1100_GS_94_0404,0409_&diagId=33_1659

However there could be a whole host of causes, so research will be needed - to start with, try putting the bike on it's main stand, select first gear & see how much free play you have in the drive train when you rotate the rear wheel back & forth. Any strange noises, worn bearings, odd clicking sounds?

 

[Two wheels good]

Driveshaft was my first thought too. Did he inspect the splines on clutch plate and input shaft?

 

[Quicktoys2]

Driveshaft was my first thought too. Did he inspect the splines on clutch plate and input shaft?

He has taken the entire apart and every part seams like it's in perfect condition.. The weakest link (more weathered) would be the driveshaft but there doesn't appear to be anything weird... Do you think maybe he should change the rubber connecting the 2 halves of the driveshaft? Could that be causing his problem?