Topic: Running on three cylinders

[gnanner79]

I have a 1974 CB550 that is currently running on three cylinders.  The cylinder located on the far left does not seem to be doing anything.  I have checked and the cylinder has great compression.  I'm thinking that the issue is in the carb.  Any thought sor suggestiosn?

Thanks,
Shawn

[gold01ca]

checked spark to the guilty cylinder?

[TwoTired]

You can also swap spark plugs with a known working cylinder. If it follows the plug could be the plug.

Also, see if the spark plug is wet (fuel) on the dead cylinder.

Cheers,

[OldSchool_IsCool]

Also make sure you have the correct suspect cylinder.  It's header pipe will be cooler then the rest.

[bryanj]

Likely suspects in order:-
(1) Plug cap
(2) Plug
(3) coil wire
(4) carb idle system

[andy750]

Also check for oil coming out of your exhaust on the guilty cylinder side....leaky valve oil seals will stop a cylinder firing - also check the plug for oil on it. Been there done that :-(

Hopefully this is not whats wring with your bike!
cheers
Andy