Hi,

I have a 1987 Vulcan with about 8,000 miles on it. About three months ago I had the carburetors rebuilt, and I changed all the oils. Now sometimes I smell gas when ridding and when I shut it down. It runs ruff, and smokes a little. I replaced the plugs, and air filters. The right rear plug was a little fouled. All vacuum hoses look good. The battery is fine. All cells are good. Could this be an ignition problem? If so how do I check it?

Thanks

 

First of all welcome to the forums. It sounds like you could have a float or needle seat sticking and dumping too much fuel into the bike. What color is the smoke?

 

white

 

Welcome to KF!

What elevation? Idle speed at around 850rpm?

edit: were the cvk's synched after they were rebuilt?

 

80'
I don't have a tach. I never touched it.
Yes, they were synched from a well know mechanic.

Thanks

 

So at what speeds are you talking about then? Low spd, Mid, High?

 

At idle it smokes, and if I give it throttle. The cylinder compressions are within normal limits 119 psi. Now I think it's the valves.

 

If you are suspecting the valves or even the rings, do a leak down test.

 

Ultra low mileage bikes always seem to come with a stack of problems like this. If the bike's sat around unused, and been left with used oil in it, there could be all sorts of nasties lurking in the motor.

If it's smoking when it's warm, is it using oil? Do you do enough miles now to know if it is?

If compression is OK it points toward valve guide wear (not enough miles) or seals. These might have perished with age. Also look for a blocked crankcase breather or even a dirty air filter.

The rebuilt carbs should have been synchronised. It's possible that one of them has a sticking needle valve in the float bowl, or an incorrectly set float height. Is the choke operating correctly?

I assume you've put new plugs in it?

Rob

 

Since you had the carbs rebuilt, sync 'em...
Their out of sync. and the lean carb controls idle while the rich carb dumps too much fuel in the cylinder....


the fix?
Get the carbs syncronized...and dealership will do it for a few bucks...