Hey all, long story short. Sold my 400 and bought a 450r instantally missed my 400 so i bought a 02 for $800. Runs awesome with no issues except at random there is a clicking or rattle noise coming from the motor atv at idle. As soon as you tap the throttle it goes away completely and will no come back till random other idle. I changed the oil and filter to see what was in there and nothing no a spec or medal or anything. Also changed the plug and adjusted the valves with no improvement. Timing tentioner pulled out and functions as it should. Any other ideas?