450 service and maintenance

Hi and welcome. The maintenance schedule for my 03 650 is as follows.
Oil - every 10 hours although I do it every 5 and filter every 10.
Valve clearance - check every 30 hours, this is a must if you want a berg to start well and save your rocker arm bearings from collapse.
Piston & rings - inspect 100hrs, replace 200hrs. I looked at mine at 110hrs and it looked good apart from a bit of scoring, changed the rings anyway and performance was improved noticably.
I would imagine the schedule is quite similar to your KTM. Bergs do take a bit of up keep but once you've found your way around the engine it really is a doddle, oil and filter change is 20 mins max, valve clearance takes a while at first if you do it with feeler gauges but most here use the 1/6 turn method (do a search on it, lots of info) which once your used to it takes 1/2 hour.
I suppose I'm a bit biased but I think they're cracking bikes.
If you get stuck we'll all be here to take the p1ss.

Regards Freaky