'82 GS750T Clunking Noise, Unknown Problem

[jonp84]

Hi,
I have an '82 GS750T. At rpm''s below about 4k, there is a loud, non-rythmic crunching/clunking noise. I suspected it would be either the clutch or transmission, but I removed the oilpan and visually checked the transmission and oil pump, and have completely disassembled the clutch, and none of these areas has any signs of malfunction. I also checked the chain/sprockets and nothing seems to be wrong there. Any ideas? The problem arose after a 600 mile road trip I took, which was the first long trip I had taken on the bike. I had used it for commuting for a few months prior to that. The first to second gear shift had gotten progressively more rough, to the point that sometimes it would not shift until I tried several times. I figured the transmission was having problems (this was my first bike so I had to learn now to use a clutch and not shift roughly), but it passed my visual inspection. The noise sounds as though there is a lose part that is getting tossed around inside the engine by a part that rotates with the engine rpm''s. If anybody has any ideas I would really appreciate it!

[mydlyfkryzis]

Cam Chain, Cam Bearings? Cam chain tensioner?

these are likely suspects.