Hi-
I've got an '82 Yamaha Maxim XJ750J with 21,600 miles on it.  It's an unstoppable bike and I have to admit I've been REALLY lax on maintanence.  This summer I've been riding it alot more and lately, the engine starts well but now the engine races ( I mean the tach says the engine wants to do 4-5,000 rpm between shifts.  The choke is not on and the throttle cable is free.  Also when I start the engine when it's warm, it does the same thing.  The engine revs really high then will settle down to idle in a few seconds.  Any ideas where I would start looking for the problem and will I be able to fix it myself ( hate to sound cheap but it''s got almost 22,000 miles on it!).
Thanks-
DMitz  

High revving and eventually settling down sounds like a possible lean burn.

Test 1, goose the throttle, does it go lower afterwards? If yes, you need the carbs adjusted.
Sorry, don't know test 2... failed test one. I suspect it would involve a dyno.

if it's a simple lean burn, Cruiser in tech tips covered how to do a proper tune up on the carbs, from pilot thru main jets. I'm not a mechanic, but, the steps made sense, and if you know where the parts are that they talked about, it should be a doable at home.