R1100GS vibration.

[Deleted account 111026]

I've a 1994 R1100GS with an M94, (early type), gearbox. The bike has covered 97K km and has developed, over the last 1K km, major vibration.
The inlets are balanced perfectly both at tickover and higher rpm.
Did anyone else who has experienced a gearbox failure encounter increased vibration before the box failed?
Thanks.

 

[Colban]

I've a 1994 R1100GS with an M94, (early type), gearbox. The bike has covered 97K km and has developed, over the last 1K km, major vibration.
The inlets are balanced perfectly both at tickover and higher rpm.
Did anyone else who has experienced a gearbox failure encounter increased vibration before the box failed?
Thanks.

Is it engine vibration (varies with RPM) or road speed vibration (coast with clutch disengaged).
Do you have Tourances fitted.They can wear oddly and cause vibration.
Does the problem only happen when braking ?.
Is everything tight?.
Have a read here about gearboxes.
http://www.largiader.com/

 

[Deleted account 111026]

Thanks for the reply, no TKs, no loose fasteners, vibration worse when under load, does vary with rpm.
Coasting doesn't tell me much as the transmission is not under load.
I'm 99% certain it's the gearbox and I'm planning to change it in the next few weeks, (I've 2 spare M97 'boxes fortunately), but I'm curious to discover whether increased vibration is a common occurrence.

 

[Dragon Master]

I've a 1994 R1100GS with an M94, (early type), gearbox. The bike has covered 97K km and has developed, over the last 1K km, major vibration.
The inlets are balanced perfectly both at tickover and higher rpm.
Did anyone else who has experienced a gearbox failure encounter increased vibration before the box failed?
Thanks.

Dunno if this will help any, but...

I replaced my m94 box last October. I fitted it in March 2001; all was well until about November 2001. coinciding with an oil change, it gained whining and rattling noises. But I continued running it until last October, during that time it covered in excess of 40k miles. I eventually removed it when a new sound developed; a sort of groaning as the clutch took up the drive. I've recently stripped this box, and the tapered roller bearing at the rear of the input shaft is, well, shafted. But at no time whilst this box was fitted did I encounter excessive vibration, and the box did not actually fail.

Obviously other things might go wrong with boxes, but I don't think your symptoms suggest the same problem I've had, i.e. rear input bearing damage.

Cheers,

Dave.

 

[Deleted account 111026]

Think I've found the cause of the 'vibration'. I had an exhaust stud removed recently and the instructions were to remove it with an end cutter on a mill...however, when I collected the head, the stud had been removed by locally heating the head with an acetylene torch.
The head was replaced and, even after re-torquing it, there was an oil weep on the front face.
I assumed the RHS head was distorted and removed it this afternoon for skimming. I could see from where the oil had been escaping and discovered that the top RHS dowel was rigidly clamped by the head gasket. None of my old head gaskets held the dowels tightly, I now believe this problem has prevented the head from compressing the gasket properly hence leading to this weep.
A couple of years ago I had to return a head gasket as one of the dowel holes was about 0.1mm undersize, on this occassion it wouldn't pass over the dowel.
BMW quality control?
The lower inlet valve is showing signs of oil contamination, this would lead to the lumpy running symptoms.
I've checked the head for distortion and can't find a problem.
Will have to see how everything performs when it's all replaced.