Engine noise Yamaha FJR 1300 2005, rattling sound at idle, goes away with very hot engine temps. The sound started very small maybe a tap here and there at idle. Now its very noticeable. I checked valve clearance and cam tensioner- (good), I just tried adjusted balancers, did not correct the noise. What is the problem? 28,000 miles on bike.

I would be looking again at the cam chain tensioner. I have replaced 2 on my 05 so far and it was doing the same thing. the other known problem for noise in the engine like that is the valve guides are know to wear prematurely on 05's and the 03 and 04. Yamaha knows about the problem and will fix it under a one time warranty even if you do not have the extended warranty on the bike. Make sure you talk to the dealer about premature valve guide wear.

BENT A ROCKER