Last month I was at a local trackday, heard a strange "crunch" but thought it was the student ahead of me touching a peg. I pulled into hotpit and was idling for a moment while waiting for another student to come around and the bike stalled out. It would turn over, but wouldn't start back up. Got back to the pit and it wouldn't turn over at all, solenoids were clicking and it tried... but seem like the starter/clutch was seized. So I thought maybe the starter clutch had died somehow.
Got home, pulled the LH cover fully expecting to find sheared teeth or chunks of a started sprag... but everything was fine but ok, thats's good? Well, was going to check the valve clearances during the off season anyways might as well get started while looking for the issue!
Pulled the valve cover and immediately found the problem. Cam chain had loosened, jumped some teeth and bound up... I mean, I guess it could be worse. So I retimed the cams and reset the tension (P.O. had put in an APE manual tensioner) and everything turned over by hand just fine. So I started checking valve clearances. After turning the motor by hand a few times, the cam chain jumped again. WTF! So I pulled the RH side cover and low and behold... the cam chain guide was dangling in a most broken way.
Leak-down test revealed what I feared .... cyl #2 has bent intake valves.
... I haven't pulled the head just yet, but I'm praying the piston is ok. So I ordered a head gasket, new nuts/washers, side cover gaskets, 2 new intake valve, and the race tension/guide combo
. 1-2wk shipping, fine. Then I get an email - BACKORDERED UNTIL MID DECEMBER
Guess I won't be riding my 675 at COTA over Thanksgiving.
The real irony here is I bought this bike earlier this year when my beloved SV650 died... at the same track (we don't ride that one often)! So I've got the Triumph cylinder head to rebuild & and re-ring the SV650 rear cylinder all the while my wife points out that her Hondas are running great and I can borrow one....