R850R Topcase problem

[jkrijt]

I have a BMW R850R from 1995 and recently I bought a Givi monokey rack and a big Givi topcase.
On previous bikes, i always had a topcase and never had a problem but with this topcase on this BMW makes the bike feel unstable.
Is it me or is this a common problem and how do I solve it ?

[richard t]

I've had a big Givi on my 1991 K75 standard for years never had a problem what type windscreen do you have? steering bearings good? tire press ok

[jkrijt]

I have the original BMW windscreen, bearings are good, tires are rather new and tire pressure is checked.

[wookie]

Is your topcase overloaded?

[richard t]

let us know when you find the problem

[richard t]

just to check you might take the case off and see if the problem goes away. maybe check it with a lite load ect

[Rob Frankham]

One thing worth thinking about is whether the top box is making an existent problem worse. If the machine has an tendency to be a bit unstable, then putting weight in that sort of place can often make something that is normally undetectable, worse. While I'm not a fan of top boxes (I can't really think of a much worse place to add weight to a two wheeled vehicle then high up and overhanging the rear of the combined contact patch), I would be inclined to check all of the other causes of instability before 'junking the trunk'.

Steering head bearings, swing arm bearings, wheel bearings, shock absorbers, wheels, tyres, tyre pressures & etc. etc.

Rob

[jkrijt]

Wookie: No, loaded (not very heavy) or unloaded, the same problem
richard t: Without the topcase it is a perfect bike, no problem at all.
Rob Frankham: I only have a problem with the topbox and not without. I never have a very heavy loaded topbox. The main function for me is a place to store my helmet and satnav when parked and my camerabag and some small items when riding.

[Rob Frankham]

Just because you've never had a problem, doesn't mean there isn't a problem. It might have just needed the top box to push it over the edge to instability. In fact, of course, that's just exactly what's happened. Fitting the box has pushed a normally stable bike over the edge. The question is whether there is something not quite right about the bike in the first place that made it happen. I would still be checking all of the things I mentioned.

Rob

[jkrijt]

I bought a smaller topcase and the problems are gone.