Timing light peculiar behavior

[Frozen Gopher]

1982 CB750F. Owned since new. Been chasing down what started as a cold-pipe gremlin that would move between cylinders. Found intermittent coils (check good with multi-meter) and things improved temporarily. Now back to cold pipe #4 at idle. Carbs have been cleaned multiple times. (of course idle circuit still usual suspect)

Question. When I hook up my timing light, the thing does not strobe until about 1800 rpm. This is not true on other motors like my 1973 Ford Truck.

I also tried it with an external/separate 12 V battery to power the timing light in case it was a charging issue. Same result.

Seems odd to me, and it does it on all the plug wires - not just #1. Does this point to anything in particular?

Thanks.

 

[mrtwowheel]

Hmmm, puzzling.

 

[Frozen Gopher]

More to the story...

It finally occurred to me to check the other plug wires, even if unusable for timing. #4 produces no strobe at all, #2/#3 are good strobe, and #1 only with higher revs.

Coils are new, and it ran well for a short period after they were replaced, so thinking it’s the 1-4 pulse generator which is stock OEM. Looks like joining the legions to go with Dynatek.

Is there a good source of those people know? Is the 2000 model the “go-to” version? Can I just get the trigger plate, and not the entire system?

I put a breaker-less ignition on my old truck. Worked fine with existing coils.