76 xs650 right cylinder problems

[TwoManyXS1Bs]

A sudden, catastrophic event like yours would likely be:
Carburetion - momentarily clogged jet, or something.
Ignition
Sticking valve

My similar scenario, long ago, was an intermittent power connection to one of the coils, within the harness connector.

Could try (each individually):
Swapping the coils' power leads.
Swapping the coils' condenser leads.
Swapping the coils' points leads (must switch plug wires too).

If the problem switches sides, suspect the harness and/or connectors...

 

[harpo57]

[Heres my right side cyl. trouble....

 

[harpo57]

Thank you for the offer of help. I will need plenty! I just got this project as is disassembled basket case. Seller suspected intake air leak. I am researching if a engine cyl./top end rebuild kit is available. Major parts and all the gaskets/seals and little crush washers, cam guide stuff... etc.

 

[Jacob Canada]

Your description is almost textbook for a baffle coming loose and blocking the exhaust.... It's abrupt, restricts pressure and reduces noise. Try taking the muffies off and see what happens.

So come to find out who ever owned the bike before me putt baffles up in the header pipe? Pulled both mufflers off and took an old throttle cable up into the left side and it went all the way up. Put it up the right side and it stopped about 15in in. So I took the old wrap off the header pipes low and behold was a nut holding the baffle in. 1 slide hammer and 10min later it was out. Left side must have came out while riding. All that work for something so stupid and small. Oh well bike needed some upgrades anyway. Thanks for all the help this forum and its members are a great thing! Chat with you all soon. See you on the road. Cheers!!

 

[Jim]

Thanks for the update. Now forum members can add baffles to the list of stuff to check with an abrupt change in one cylinder.

 

[mrtwowheel]

No wonder you were "baffled".

Scott

 

[grizld1]

Congrats, Jacob! It slipped my mind, but I should have thought of a similar problem that I ran into a few years back. Symptoms were similar to yours.The owner was an old hand who was refurbing a new acquisition that had sat for a few years, and he was stumped. He asked me for advice by email, I looked over what he'd done, and I was stumped. He took the bike to a shop run by a real oldtime mechanic (not a "motorsports technician"). The proprietor listened to the owner, listened to the motor, and nailed the problem immediately: "You need a new headpipe." Water had gotten into the vent in the outer wall of one pipe. When the water froze it collapsed the inner wall, closing off the pipe enough that the cylinder couldn't breathe.

 

[Jacob Canada]

Thank you all for the help!!