Bought a used 08 GS1200 which, unknown to me when buying, the previous owner had de-catted. He had made a very good job of cutting and rewelding the cat section of the standard exhaust system. The modified exhaust was supposedly not noticed by a BMW main dealer (Dundee) who then sold the bike to me as 1 year old approved used BMW. Anyway thats a different story 
Bike also had a rather nice BOS end can fitted.
The de-catted bike tended to run hotter than my current 2010 GS and, on several occasions at altitude in the Alps, the temp gauge actually reached the top of the range. Never seen similar temperatures on any standard BMW I have ridden. De-catted was okay in the UK but a mix of higher European temperatures and altitude meant the fuelling mix was way outside proper operating limits.
As others have said, the later model GS's run far leaner fuelling than earlier models. Personally I would not de-cat late model GS's as the risk of lunching the engine increases.
If budgets allow just buy a 2010 model and the DOHC engine dosen't need de-catting; it already revs higher and runs smoother than previous models.
Bike also had a rather nice BOS end can fitted. The de-catted bike tended to run hotter than my current 2010 GS and, on several occasions at altitude in the Alps, the temp gauge actually reached the top of the range. Never seen similar temperatures on any standard BMW I have ridden. De-catted was okay in the UK but a mix of higher European temperatures and altitude meant the fuelling mix was way outside proper operating limits.
As others have said, the later model GS's run far leaner fuelling than earlier models. Personally I would not de-cat late model GS's as the risk of lunching the engine increases.
If budgets allow just buy a 2010 model and the DOHC engine dosen't need de-catting; it already revs higher and runs smoother than previous models.
