exhaust popping out one side

[Tom Andersen]

1978 XS11 is popping out the right side muffler at idle and through higher rpm. It has been sitting for a few months. Any suggestions?

[DiverRay]

run some seafoam or berryman's B12 through the tank. Add about 1/2 cup to a half full tank and ride it for a few miles. If that does not work, you will need to pull, clean, and re-sync the carbs.

[Tom Andersen]

run some seafoam or berryman's B12 through the tank. Add about 1/2 cup to a half full tank and ride it for a few miles. If that does not work, you will need to pull, clean, and re-sync the carbs.

DiverRay,thanks for the quick response. I have already added Sea Foam, I will ride it and see what happens. I have mercury sticks, if need be I'll sync them or clean.

[bikerphil]

Check the vacuum caps on the carb boots, could be leaking.

[motoman]

DiverRay,thanks for the quick response. I have already added Sea Foam, I will ride it and see what happens. I have mercury sticks, if need be I'll sync them or clean.

Pertaining to syncing the carbs, having run engine till at normal operating temp., FIRST set idle mixtures, backing out one mixture srew, then slowly start back in with it JUST till a constant change is heard. Then back mixture screw out 1/8th of turn and no more than a quarter turn. Do each of other three mixtures screws same procedure. Now using your manometer, sync the four carbs. Go back and repeat mixture screws settings procedure, then check sync and adjust as necessary.......done.

[cajun31]

Pertaining to syncing the carbs, having run engine till at normal operating temp., FIRST set idle mixtures, backing out one mixture srew, then slowly start back in with it JUST till a constant change is heard. Then back mixture screw out 1/8th of turn and no more than a quarter turn. Do each of other three mixtures screws same procedure. Now using your manometer, sync the four carbs. Go back and repeat mixture screws settings procedure, then check sync and adjust as necessary.......done.

sometimes messing with those idle mixture screws before synching the carbs makes it harder to get them synched. Of course I am talking about a set of carbs that are new to you. If they have been running on your bike they are probably very close and what Brant has suggested will probably work OK. If not then you might want to start with each screw lightly seated then back off 2.5 turns. Synch the carbs... adjust each screw... and if possible use a color tune to accomplish that. Turn each screw in or out until you just see the hint of orange in the color tune view glass. Synch the carbs again and you will be spot on. If you still have popping out of the exhaust then you have a leak. You will find it almost impossible to sync the carbs if it is an intake manifold leak. If you have an exhaust gasket problem then you will notice popping on decel. Good luck... hope you get things worked out.

[Tom Andersen]

All good suggestions, thanks to everyone. It's up to me now.

[skids]

Fouled plug, ancient plug wire, bad connection between plug wire and plug, Cracked nipple on carb boot, are suggestions to check in addition to the above.

[Tom Andersen]

Fouled plug, ancient plug wire, bad connection between plug wire and plug, Cracked nipple on carb boot, are suggestions to check in addition to the above.

skids, thanks, I will add this to the check list.