R1100gs

Can anybody tell me why my bike misses badly when she is hot. i,ve only just bought it and it has no service history and an after market simus pipe if you hold the throttle at about 3500rpm in any gear it feels like a restriction some where, air filter is clean and bike has done about 20,000 miles where should i look first or would it make more sense to get it serviced by a dealer and then see what happens. does the computer often goe wrong?

Stuart,

I don't know your history with BM's or if you are a Mechanic so here are a few things to try if you already havn't already done so. Im not sure if you know much about the condition of the spark plug's? You could have a look at them. They might need changing. There sould be a spark plug wrench in the toolbox under the pillion seat. Before you remove one give the recess a wipe out so none off the dirt that builds up there can get into the cylinder. if your bike has a aftermarket exhaust it may be running a little lean, you could ask at a dealer about this, I don't think it will cost much to have the mixture adjusted. If the plugs look ok, maybee check that the leads are OK and fitted corectly to the ignition coil under the tank (they should be they don't come off easly) as for the computer, this is a Motronic system that is very reliable as far as I am aware, it is unlikely a Motronic fault.
It will be worthwhile checking the throttle cable sleeves are in their housings properly. they are located behind the black plastic tubes that come out of the airbox and in to the cylinders, they look like bycicle brake cables. If your bike has been stood for a while the fuel may have moisture contamination, Shell Optimax has been rated as a good choice for the GS on this board in the past. Hope you get it fixed and enjoy your new bike

Andy

Sounds like surging to me. Delve into yer fusebox, take out the cream coloured coding plug, a plastic box about 30mm square. put in left pocket of jacket and try it..........worked for me