hi there. i have recnetly bought a wr400 2000 model. since i got it i have noticed a rattle noise comig from the engine. now it sounds like it is pinging to me. noise seems to be coming from the top end and more noticable on the left hand side of the bike (if sitting on it) some background info. it does it in any gear (higher gears more noticable) does it at the same RPM regardless of gear (low- mid range) does it even when NOT underload (down a hill) (worse tho when underload i think) bike is running high octane fuel does it when cold/hot happens only at a certain rpm and goes away when revs drop/rise just that little bit. motor revs/idels/starts very well. no other noticealble noises. now.....i have done some searched on this site and some ppl said to check chain tension. my chain IS a little loose - but i dont see why that would be the problem as it only makes the noise at a certain RPM and reglardless of gear..... im yet to rev the engine slowing in neutral to see if i can hear it at the same rpm.... does any one have any ideas of whats wrong? or what i can do? thanks!