1250 rear wheel vibration

[Littledumptruck]

Following a mate on his 1250 on Monday on the A1M I noticed his rear wheel bouncing constantly unlike two other mates on an identical 1250 and earlier 1200, so not road surface. I’ve spoken to him about it and he’s going to get new tyres for a big trip pretty soon, but he did mention he’d just had the driveshaft replaced by BMW. So I’m wondering if they’ve got the positioning or phase wrong. Seem t9 recall reading somewhere that the UJs have to aligned correctly for some reason I can’t remember. If they’re not aligned correctly could that cause such a vibration?
Obviously a shock service would be next if tyre balance is ok

 

[Pale Rider]

Id be inclined to think the shock has had it.

 

[jefformston]

Following a mate on his 1250 on Monday on the A1M I noticed his rear wheel bouncing constantly unlike two other mates on an identical 1250 and earlier 1200, so not road surface. I’ve spoken to him about it and he’s going to get new tyres for a big trip pretty soon, but he did mention he’d just had the driveshaft replaced by BMW. So I’m wondering if they’ve got the positioning or phase wrong. Seem t9 recall reading somewhere that the UJs have to aligned correctly for some reason I can’t remember. If they’re not aligned correctly could that cause such a vibration?
Obviously a shock service would be next if tyre balance is ok

I think the UJs are keyed so they can’t be out of phase.

 

[Littledumptruck]

He dropped the bike into North Oxford for them to suss. They’ve balanced the wheel and handed it back. Trying to persuade him to come out for a spin with me again so we can check it’s cured before he sets off for the Dolomites in a few weeks time.

 

[autogs]

I think the UJs are keyed so they can’t be out of phase.

There not

 

[Neil W]

I would get the wheel checked on a balancing machine , it could be ovality of the tyre or the wheel has gone out of true and is slightly oval

 

[TaskMule]

I think the UJs are keyed so they can’t be out of phase.

Ujoints are part of the shaft, they don't need to be "keyed" to anything

 

[jefformston]

There not

They aren’t on my 2001 1150 but I’m sure on later mode they are so can’t be reassembled out of phase. Steptoe or DrFarkof will know.

 

[TaskMule]

They aren’t on my 2001 1150 but I’m sure on later mode they are so can’t be reassembled out of phase. Steptoe or DrFarkof will know.

Universal joints are always in pairs offset by 90 degrees, this can never change. The splines have nothing to do with it

 

[mikeyboy]

Universal joints are always in pairs offset by 90 degrees, this can never change. The splines have nothing to do with it

1100 and 1150 shafts were in two pieces,
Late ones had a master spline,early ones did not,
So jefformston is correct ,however this does obviously not apply to later bikes
I’d agree with other posters,
The rear shock is fucked