Upt to 2002 the forks were a pale colour after march 2002 they came as blued steel like a rifle barrel and are much more hardwearing and the Evo 2 gearbox.
You should look for corrosion at the bottom of the forks and around the boltholes of the forkbrace, if its been out in salt and not washed immediatley the salt gets in the boltholes and flakes the paint off, if the owner has had half a brain then he will have filled these bolt holes with WD40 and or Chain wax which stops the problem developing.
The Throttle bodies should be checked for wear, see if they wiggle around ask the owner if they have been replaced and if he has lubricated them, a drop of oil at the TB bearing stops the problem.
From 2003 the twin spark was introduced, no performance difference just an emissions change and Evo 2 ABS power operated brakes.
Fuel gauges often show low levels even when brim full and this is due to a surface build up on the wiper assy in the tank as the wiper is exposed in the fuel, it needs a clean at the 12,000 intervals which is not specified in the proceedure, its easy to do but requires the tank be more or less empty, its no real problem but it is annoying till you fix it, the proceedure is detailed on another thread with pics.
Check the rear wheel bearings for wear, bike on centre stand and try and move the wheel lateraly, it shouldn't move more than a couple of mm at the edge of the wheel, again if the owner has repacked the bearing at each tyre change then all will be well.
The GS 1150 is not rocket science, nothing on it is difficult to maintain and its all easy to get at, common sense at the maintenance proceedures stops all the problems in their tracks.
Generally look for the signs that the bike has been looked after, road salt in winter wreaks havoc with aluminium and it can all be easliy washed off but if left will cause rapid corrosion, look under the tank at the fuel pump access, this is steel and if the bike has been out in salt and not washed it will corrode quickly.
Buy privately so you can talk to the owner, you'll get more of an idea how the bike is by the attitude of the owner, if he looks like a numpty then walk away as the bike will have been neglected if he looks like a technically minded person then more than likely the bike will have been looked after. In general the dealer has to make £1000 on a bike to cover the showroom costs,warranty and some profit, a private buy should be between what the trade in and showroom price would be, so both parties will get a better deal.
Service histories don't mean much if the dealer is crap so find out who your local dealer is and where the bike has been serviced, for example the service history is from SPC or most other dealers in London then its worthless, but if its from Rainbow, Pidcocks, Baldersons then you can be sure the technicians are first class and the work has been done properly. Don't be put off if the owner has done the work himself it may be better than the dealer, and if he has then he should have kept the bills for the parts, I maintain my own and keep a detailed Excel spreadsheet of every mile i cover, every litre of fuel and everything I do in maintenance or changes.
There are no real issues with the 1150, progressive changes were made up to the introduction of the 1200 which is a radical change a different animal altogether.
No problem with accesories there are rafts of stuff for 1150's on this board.
Good luck and enjoy
