74 Buffalo, Left plug fowling often--blackening

[TheMarkedMan]

My 74 GT750 is running great after being in storage for almost 30 years.
Problem is: left cylinder, when it's running, is running much colder than the middle and right ones....
Eventually, the plug will foul...when I pull it out, it's black...the others are a nice true butterscotch color.
I heard it may be the SRIS lines...somehow resulting in too much oil in that cylinder--baking it to the electrode, shorting it out? Does this make sense?
Can anybody explain this to me, or help me at all?
Many thanx!

[rbond]

That will depend on whether it is wet fouled or dry. Wet usually indicates too fuel rich, also if it 'gooey' it could be oil fouled. I would almost eliminate ignition problem, it sounds from your description, I have been fooled before. Also check the exhaust baffle, it may be plugged up causing extra back pressure, it could even be a bad crankseal. A leak down test might need to done. There are sooooo many things it could be, everything else can cause the same problem, it will be a test of your patience checking to find the problem. Two strokes have a lot to work with for being a simple engine!?

[jkevinlilly]

You do have the choke lever in the off position right?
Don't laugh, I rode a GT550 for years, and the first time I was on a 750 I rode a 25 mile round trip and almost did not make it home due to fouled plugs. Because I was riding it with the choke on.

The reason? The on/off positions of the lever for the choke is exactly backwards on the 74 750, compared to the 76 550.

Kevi

[cutlass79500]

also check the float level on that carb all that sitting could have a small pin hole in it. Or just might be out of spec. Also check the spark cap could be going bad or coil