Popping in exhaust

[Incubus]

Hi Guys, it has been a while since I rode my XS11 regularly, and a while since I spouted regularly. But the bike is back out and here I am.

Since bringing Incubus out of her slumber, I noticed something I do not remember from before. At low speed cruising - say, 30 mph in second gear - the exhaust pops. I am kinda used to exhaust popping while decelerating - most of my bikes do that because of exhaust leaks - I am not used to popping while riding at a constant velocity.

Is this also just an air leak into the exhaust? I figure its more likely is something to do with the carbs, which are the root cause of all XS11 problems, even flat tires, but I am not sure what would need adjusting. The bike is running well with a good idle and smooth acceleration off the line, and even when the exhaust is popping the bike seems to ride just fine. It just doesn't sound great.

Any suggestions?

Patrick

[skids]

I don't know for sure, but it seems to be ignition related. I would start by using contact cleaner at the brain box connectors and also check the resistance between spark plug wire pairs (boot to boot). These are easy and quick just to see the effects.

[Schming]

Check your mufflers for a rust through and if they are good try going out 1/2 turn on the mixture screws.

[Bonz]

Check that your headers are tight to the exhaust ports. At idle before things heat up (or once hot, just be careful) move your hand around up there around each pipe and you can feel if there's any air moving.

Also if stock exhaust, check where the pipes bend into the collector. There is a clamp over a copper sleeve that needs to be tight and be sure the copper sleeve is fully underneath the clamp. It holds the bottom of the header pipe into the collector and seals it.

Check for exhaust or intake leaks elsewhere as mentioned, and clean the contacts on the electrical brain as Skids said. Because it is at a constant velocity, something could have turned lean with an intake leak. Cracked intake boots are something to check.

You could turn your fuel screws in til they seat lightly then back them out the same amount to see if there's anything that might be blocking a pilot orifice that the needle would dislodge. Simple to do.

Backing fuel screws out a half turn would change the mixture that was fine before.

Have you tried adding half or full enrichener lever when it is popping? Does it go away?

Are you wearing a different helmet, anything different that could change your hearing perception?

[TADracer]

Sounds like gummed up pilot circuit in one or more carbs. If it has been sitting awhile this can happen because the passages and orifices in the venture are so small. Cruising at 30, when your popping happens, the carbs are pretty much using the pilot circuit exclusively and that would not necessarily affect your acceleration or your idle.

I would try cleaning the carbys