Follow the manual, no exceptions,
-Oil change every 5k km. New oil filter every 5k km (hiflo - great deal on ebay for a 3 pack).
-Valve clearance adjustment. Had to adjust twice. Makes a noticeble improvement on idle.
-Swapped factory chain at 15k km. kinked links. rather low milage. Installed DID zvmx x-ring (overkill... but massive discount on amazon.uk for last unit!)
-K&N air filter. Got a good bump in top end power 9k rpm (but... see next point)
-Recently changed fuel strainer (some call it the filter, before fuel pump in the tank). Was having two issues: Stalling when running low on fuel (one bar flashing), but still plenty to for another 40km. Also slight loss of power at top end (9k, 10k rpm). Was not dirty... but the inner material (black) seems to have "swollen" and was seriously restricting flow. Got a OEM equivalent replacement on Aliexpress.
I have removed the fuel assembly twice, and cleaned thorougly with carb cleaner. Seems to restore a bit of top end power. Debating if its the strainer, filter or pump. I also have to check/clean injectors just to be sure.
At some point I would like to hook it up to a SDS system (suzuki computer gadget, reads parameters off the bike computer, can do some special mantainance with it). Just to check there is nothing too "off". But not sure how much that would cost (you can buy one on ebay for about $200us). Local dealer should
have one. Just a thought...
Overall I am 1000% pleased with this bike. Couldnt ask for more. First bike. Could have gone for a new, but smaller bike (150cc, 200cc), but I think I would have suffered on the long highway rides. Its been a workhorse, racking up kms like crazy. Solid, powerfull enough, easy to handle, overall cheaper parts/repairs (if you shop around...)
Hope I can hit such a good bike when I decide to upgrade