Bike is running WAY too rich.

[CZroe]

Ever since my 7,500 mile service my exhaust has smelled a bit "gassy." It got worse and worse until even my neighbors complained. After getting it serviced again recently (12.5K miles), I asked them to look into it and they said that they found nothing wrong. I drove it to work the next day and it was notably worse than before I took it to the Kawi service center... so much so that my coworker, who used to be a chief line mechanic at a Honda motorcycle assembly plant, came up to me and told me that it was "WAY too rich." He said to have them "throw the mercury tubes" on it, which sounds like "sync the carbs" but he wouldn't confirm if that's another way to put it.

Isn't this supposed to be an extremely lean bike the way it comes from the factory? I never had it jetted, shimmed, or anything. Stock exhaust and air box, new OEM filter element, etc. Perhaps this is why I so rarely break 200 miles per tank.

He also commented on the way the engine speed didn't seem to stabilize when it was fully warmed up (a little "lurchy" if you listen closely).

What could these be symptoms of? Could they be related to my unexplained breakdowns (usually at stop lights; will not start for several minutes; once, in the rain, had to push a mile to a gas station despite not being out of gas)? Should I take it right back to the same Kawi guys and tell them "It's too rich. Fix it." or am I likely to hear the same thing back from them again ("no issues found")? Could de-synced carbs do this? Thanks!

[2WheelGuy]

I'd start by doing a plug read to see if the engine is running rich and on which cylinder.

If it is I'd look the float level, choke operation.

[CZroe]

Thanks. What does float level/choke operation mean exactly? My choke cable went slack in the middle of a ride around 8K miles and now only starts to affect RPMs at the outer limit of the lever's range. I noticed because I was turning it up as I coasted to a stop light when I realized that the bike wasn't warm enough yet (bogging engine after I left work). Are you saying that it might be doing the opposite of choking by sending too much fuel?

[demp]

Mine might be heading this direction too, I've found that lately I'm losing mileage and it does smell more gassy than it used to

[2WheelGuy]

My first step in diagnosing carb problems is to pull the spark plugs. They should be clean and slightly brown in color. If the bike smells rich and one of the plugs is black or wet you've narrowed down which carb is the culprit. I'd check the float level in that carb.

You said the choke cable went slack. That would suggest that the choke is stuck on. The choke on your bike is an "enrichment circuit" which means that it adds fuel to the mixture, as opposed to the traditional method of "choking" off the air supply. A stuck choke would be most noticeable in low speed city riding. Remove the tank and check the choke function.

[backinthesaddleagain]

Any chance the air filter was serviced and excessively coated with oil? Over time some will drip off the filter but some will be drawn into the engine and maybe foul a spark plug.
Posted via Mobile Device