Hello, picked up this decent '83 xr500 a couple of months ago and have been noticing that in 3rd gear, when I accelerate really hard, the bike kinda shudders in and out of gear or something is slipping. I haven't really noticed it in any other gears, of course 1st and 2nd I'm not in very long and haven't had enough room to get to the top of 4th. Just wondering if it is clutch slippage or something with 3rd gear itself. It does have a new chain and sprockets and the engine is tight, just dont' want to dump more money into it if the problem is something other than just rebuilding the clutch. Any help would be much appreciated.