[sickstyle]

hey all have a question regarding my 1984 cm450e. I'm running on one cylinder my left side. I checked spark I have spark ,I pulled plug and checked compression with my finger seemed to have enough but will do a compression test this weekend. and I checked my float bowl drain and there's fuel in it so in pretty sure I'm getting fuel. plug is wet. so if I'm getting air, fuel, spark, conpression. why am I running on one cylinder ?

 

[sickstyle]

black plug is the running side and the wet n lighter one is the none running side

 

[mike in idaho]

Try swapping the plugs, side for side.

 

[daktah]

if you are getting spark then both plugs are firing because of the single coil design. same thing with timing. the fuel charge may be way too rich or way too lean to fire. even though the bowl has fuel you may have plugged jets or a stuck throttle slide. the compression might feel good but it might in fact be too low to get good ignition.

 

[Yendor]

Not so true on both plugs are firing.

More than once I have tested for spark with the plug out of the cylinder only to find it would not fire under compression.
Buy NEW Plugs and give them a try.

Both plugs show evidence of carbon fouling from a rich mixture.

Also testing for compression with your finger over the spark plug hole pretty much tells you nothing.

Even a cylinder with totally blown rings and bad valves will give you enough to push your finger back.

 

[dtsmjr8dan]

I see your biggest problem...CHAMPION Spark Plugs. Hondas don't like them. Get a set of NGK D8EA. CTC sells them. Try not to get the DR8EA (resistor plugs). I know that they list the DR8ES for the CM/CB450's, but the non-resistor plugs are better.
I'll look. If I have a spare set on hand, I'll bring them with me tomorrow with the air box.

 

[daktah]

More than once I have tested for spark with the plug out of the cylinder only to find it would not fire under compression.

But because of the single coil doesn't the spark current go through one plug, though the block, then the other and back to the coil? If so then if you break the circuit by one plug not firing regardless if it works out of compression or not and both plugs won't fire. Or am I wrong and it's actually a center tapped style where both plugs have their own path to a common coil ground?

 

[Yendor]

The Plugs have to be their own separate Dead End to Ground Paths.

I suspect but don't know for certain, the Coil fires on the compression stroke for both left & right cylinders and it just wastes a spark on the side that has no Air Fuel Mixture & Compression at that time.

 

[daktah]

i figured that might be the case. and yes it is for sure a wasted spark system.