Join Date: Apr 2007
Location: Oxnard, CA, USA
The official service interval is every 18,000 miles. Once the valves are in spec they rarely move, although it can happen so it's still a good idea to open the bike up and verify.
Also, it's a great time to completely clean the outside of the radiator (front and back), as the small spaces between the radiator fins can get gunked up with road grime and thus drastically reduce the cooling efficiency. That isn't part of the official BMW spec, but most dealers will do it if you specifically ask them to, and the good dealers will do it even if you don't ask.
And if you do the service yourself, then definitely give the radiator a good and thorough cleaning.
Also note that BMW calls for replacing the expensive and proprietary spark plugs every 18,000 miles. Some riders have been fine leaving the plugs for 36,000 or even 54,000 miles, and you can get slightly less expensive "equivalent" spark plugs and save a few bucks. Still, once you're into the top of the engine that far, it's pretty easy to just pull the plugs and drop new ones in.
'13 Dark Graphite Metallic K16GTLD, 24K miles and counting...
'09 Magnesium Beige Metallic K13GT, 60K miles miles and counting...
'02 Mauve Metallic K12LTC, 106K miles and sold
BMWLT#145, IBA# 366, MOA# 111996, SCMA# 24032
All lower 48 states plus Alaska on the K13GT in two weeks . . .
Some people see the gas tank as half empty. Some see it as half full. All I care is that I know where the next tankful is coming from...