#2 cylinder dead at low RPM

[Brent]

#2 thouthts

'79 XS1100 Special #2 cylinder dead at lower RPM. It has very nice top end, but runs rough at lower rpm. I stopped at a local park and took one plug wire off at a time and found the rpm didn't change when I removed the #2 plug wire. Ran it down the road like that and it acted the same as with the wire on.
Got home and put an old spark plug on the end of the wire and found nice hot spark. Soooo, my question is which jet in the number two carb is more likely than not the culprit?

I just got back from an "all expense paid visit" to Afghanistan, but before I left I put SeaFoam in the tank. The bike started right up, but I'm afraid maybe in spite of the preventive seafoam it may still have a gummed jet. I don't know, but before I go through the trouble of taking off the carb and cleaning it, I would run this by you guys. Any thoughts??

Ray

Ray,
This could be low fuel delivery...OR too much air from a leak. maybe not as likely, but easier to fix if it is one of the rubber caps leaking at a port used
to sync carbs. And it could be a leak in the vacuum advance line which is connected to number 2 carb.

Good luck wrenching

[XS1100_OEM4ME]

I like that

I like that. Does the snorkel missing give you much room? It seems my airbox bottoms out againest the frame with the snorkel still on

[QUOTE=bikerphil;348352]I cut the snorkel down and the air box comes out easily before the carbs, no center top bracket either.

[bikerphil]

I like that. Does the snorkel missing give you much room? It seems my airbox bottoms out againest the frame with the snorkel still on

After the bottom half is off I just tilt it a certain way and it comes out the right side in seconds.

[XS1100_OEM4ME]

You pull the whole airbox. Wow, that would give me all kinds of room to work, never thought of that, thanks, I may do the mods next time I have to do an R/I

After the bottom half is off I just tilt it a certain way and it comes out the right side in seconds.

[warlock60]

Darn Holiday, got in the way.

I never considered an air leak, but I suppose at low speed that may be likely. I haven't had time this past WE to do the deed, but this coming WE will tell.

I'll start with the possible air leak. As I said, I took the #2 plug wire off and the bike ran the same at low speed then worst at higher speed, put the plug wire back on and same at low speed and great higher speed, that's why I was leaning towards a clogged jet first. You guys seem to confirm my fear. Every time I come back from a deployment it seems I have to take those darn carbs off. I don't know which evil is greater, completely draining her and having her dry out, or Seafoaming her and still end up with carb issues.

Guess it's six to one, half dozen to the other...

I'll let you know what I find next week. Thanks for all the wisdom.

[XS1100_OEM4ME]

Gas

Do you have a friend that you can trust to ride it or at least run weekly while you are gone. Gas today turns bad if left sitting for long

I never considered an air leak, but I suppose at low speed that may be likely. I haven't had time this past WE to do the deed, but this coming WE will tell.

I'll start with the possible air leak. As I said, I took the #2 plug wire off and the bike ran the same at low speed then worst at higher speed, put the plug wire back on and same at low speed and great higher speed, that's why I was leaning towards a clogged jet first. You guys seem to confirm my fear. Every time I come back from a deployment it seems I have to take those darn carbs off. I don't know which evil is greater, completely draining her and having her dry out, or Seafoaming her and still end up with carb issues.

Guess it's six to one, half dozen to the other...

I'll let you know what I find next week. Thanks for all the wisdom.

[warlock60]

#2 Carb and new gas

Finally found time to play with the rascal. I checked the vacuum advance tube and found no leak. Checked the carb boots, yes small cracks but again no leak.
Instead of taking the carb bank off I used a mirror and some contorsion moves to take off the carb bowl, removed the pilot jet screw and blew carb cleaner back and forth through the main jet and pilot jet. There was good flow both ways and yes there was a piece of black junk in the bowl when I removed it.
Then instead of just adding a smidge of gas to the old I put fresh gas in 'er and it seems to be running smooth again.
Thanks for your advice once again.
Ray