BMW R1100GS Flat spot
 

Hi,
I have a '95 r1100gs with just over 50 000 km, recently it has developed a flat spot, which starts at about 2000 rpm.
Whilst running, it occasionally backfires, but this lack of performance is consistant right up to near red line.
My initial thought was plugs, they're ok.
my next step is to check valve clearances, however it is not indicative of tight clearances.

Any ideas please?

I would appreciate it


Anthony.

Where to start....?

Try resetting the motronic unit. Try resetting the throttle position sensor maybe get rid of your Cat code plug to let the bike run richer , check the fuel filter .... balance the throttles..... adjust the valves ; basically give it a good service and I mean 'good' service and it should make a world of difference.

throttle cables too
 

as gecko said, a good service will work wonders.
but another thing worth looking at (even before the service) is the condition of your throttle cables and pulleys. a little stone or similar lodged between pulley and cable changes everything, by making the cables pull unevenly.
your bike's prob not old enough for new cables (changed mine at about 200kkm) unless they have been kinked or otherwise damaged, but check this too.
cheers,
andy.

Hey Anthony

I moved your thread into the BMW Tech forum as it is more likely to get responses.

You could also try leaving it into Embassy Bikes in Wexford, if you haven't the expertise yourself.

You could also try the following link....lots of very specific experience

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