• Enter the March CB750 Supply gift certificate giveaway! It's easy... Click here, post something, and you're entered into the drawing!

Spark Plug Fouling

MIMRAY

CB750 New member
Messages
4
Reaction score
0
Points
1
Location
Alberta
Noticed my 3rd cylinder wasn’t firing, pulled the plug and was pretty dirty. Definitely running too rich. Put in a new plug and fired instantly, drove it for about an hour, turned it off, next start up it didn’t fire again (plug was filthy again) Would adjusting the pilot screw on 3rd carb for a for lean mix be my best bet before looking into the float, etc, or ripping apart the carb itself and diving into that? I pulled the plugs on the other cylinders and all looked fine, would I need to adjust all 4 pilot screws or simply just the one currently running too rich?
 
Adjust all screws to 2 turns and not that if done. Pilots are only for idle and have nothing to do with riding around above that.

Plug will foul quick if the cylinder is dead as in compression, run a test on them including that one for pressure and need 130+. Work on carb all day long and it still doesn't fix that.
 
Burned valves more likely............head work. Nobody ever sets the valves on these because they require shims and then the valves burn.

The rings are pretty durable in comparison.
 
Back
Top