I did 11600km (450-500hr)on my first motor. I did not touch the valves. I should of though, but i never did.
Guys are fitting HT coolers to the 450's and 525's and running them for 2-3k miles on dualsport rides. With just that little amount extra, I dont want to know what the bottomend is going through. That being said, it can be done. Doubtfull Ill ever do more the 10hours on a change.
The manual points out to change the oil every 1000km/600miles. Thats about 30hours?!?!!?
KTM Super Moto 950, KTM Adventure 950S, Honda XR650R, Honda XR125L, Husqvarna SM610, HusaBerg FS570, Yamaha YZ250WR with rekluse