Hey Folks.
I pulled the valve covers, timing belt covers, flywheel timing cover, spark plugs, generator cover, and followed the valve adjustment procedure in the manual, and valve/tappet clearances were good. I made some very minor adjustments to a couple of the valves (corrected by turning two of the adjustment screws just slightly, less than 1/8th of a turn). I found some small metal (aluminum) shavings in the oil, predominantly on the intake valve springs on the left side (Cylinders 2 and 4). I'm assuming the shavings are from whatever is causing the noise, however I will note that I have fresh oil AND about 6oz of SeaFoam in the crank case. I suspect the only other source of the shavings could be from whatever the seafoam knocked loose. (possibly from a previous issue one of the PO's had?)
The timing marks line up perfectly between the crankshaft pulley, and the timing gears both on the left, and right sides, so it doesn't appear that the timing belt jumped. The belts look to be brand new. My dad was the PO and is about 90% sure he changed the timing belts prior to parking the bike about 5 years ago. The condition of the belts basically confirms that. The belt teeth look new, and don't show any signs of wear, as described/shown in the shop manual. (Regardless, i'll change them anyway due to age.)
The timing belt for the valves on cylinders 1 and 3 (Right side as you're sitting on the bike) is loose.. Loose enough that I can turn the tensioner pulley freely with very little effort. It is TOUCHING the timing belt, but the belt isn't tight enough to keep the pulley from rotating. The opposite timing belt for 2 and 4 (Left side as you're sitting on the bike) is tighter (not over tight), and I'm unable to turn the pulley without using a fair amt of force. NGW's Shop Talk Section has an article by Octane that outlines the procedure for changing the timing belts and describes this issue, as well as outlines the procedure for correcting the slack on the right belt.
My question is:
Could this sound be caused by a loose timing belt, even if the belts indicate correct positioning, and the valve clearances are correct? Any ideas or things I can try would be greatly appreciated.
Thank you!
