V-Twin Cylinder floods frequently

I have an '84 Yamaha XV-1000 that the rear cylinder floods frequently
on. The bike has an aftermarket manifold that is set-up for only a
single carburetor. So it is obviously not that one carb. is running
richer than the other. The rear plug shows signs that it is fuel
fouled; however, I switched the plugs (front to back) and still the
rear cylinder floods. The plug that was in the rear (now in front)
looks okay and the other plug looks fuel fouled. So the problem stays
with the cylinder.

I am new to cycle repair and am unsure as to what to check next. Any
suggestions would be appreciated.

Thanks,
Larry

 

What kind of carburetor is it, a 1-barrel or a 2-barrel carb? A
2-barrel carb might have
2 idle jets and 2 main jets and one main jet might have fallen out.

Or, is the spark plug *really* gas fouled, or is it oil on the plug?
And oil-fouled plug would obviously be oily, a gas-fouled plug would be
wet and smell like---doh!---gasoline.

Then there is the possibility that your problem is a bad spark plug
wire. Some ignition system designs are simple, one coil fires two spark
plugs at the same time and it's possible to switch plug wires to see if
the symptom moves from one cylinder to the other.

And then there is the old trick of raising the voltage at which a spark
plug fires by holding the spark plug cap about 1/4 of an inch away from
the end of the spark plug while the engine is running to see if the
plug starts firing. If it does, that suggests something wrong with the
spark coil triggering mechanism or the ignition control box or shorted
high tension windings inside the coil itself.

Then again, maybe you just have a bad 12 volt connection where the coil
gets its power from the motorbike's wire harness.

 

What kind of carburetor is it, a 1-barrel or a 2-barrel carb? A

The carb is a single barrel.

The plug looks fuel fouled. The residue is not oily and smells like
gas.

Thanks for the other tips. I'll look into them.

Larry

 

How's the compression on the cylinder that fouls the plug? Are both
valves set right?

 

sounds to me like its a imbalance with the fuel atomising with the single
carb kit. not sure of the cure other then going back to the duel carb setup.
i have seen other engines like this i have put a stainless screen in the
cylinders intake thats running rich and it did cure all of them but these
were small engines kawasaki mule engines to be excact. but i dont know how
you would do that to yours. i would try to get the stock setup back

 

First off I found out that the replacement filter I used was gas
soluble even though you are suppose to oil it. This was causing some
major problems.

The trick for increasing the spark really worked well. I re-gapped the
plugs. This seemed to help a lot.

I hosed down the carb. with spay cleaner this seemed to help a lot too.