Just picked up a 01 426 that needs some tlc to get it back into shape again. While going over it I noticed a couple of things that I haven't com across on a 4stroke so far. I dropped the oil and it was really dark and thick, and well over due for a change, when I came to change the filter I was alarmed at how many metal filing there were there, possible 1/3 of a tea spoon. I've never seen as much as that before as my oil changes are normally every 5hrs, anyone seen this or would be overly concerned? The other is when I checked the valve clearance they were all tight. Again I have never had any on my bike go out of spec. Is it ok to shim them to bring them into spec or should I be really putting new valves in???