Britbike forum Forums Thread Like Summary - Request advice troubleshooting misfires.

Hello Forum
I'm still shaking out the '69 Thunderbolt I've rebuilt. The last couple of test runs an annoying misfire | has developed. When it occurs, it is very brief | only an instant. Occasionally it presents as | BANG. This | problem presents mostly at higher RPM, but | occasionally during acceleration. I might cruise along for many miles with no issues. Other times | it will | BANG with more | frequency. I'm using Power Arc ignition. These | BANG events are random. I have examined | the connections from | battery to coil and found | BANG no issues.

Can you offer any advice on troubleshooting such intermittent interruptions?

I'm worried one of these hic-ups might turn into a hic-
and leave me stranded.

Thanks

These are the symptoms I get when the ignition switch is failing, a couple of cycles of no spark then a bang in the exhaust when the spark comes back, stick an ohmeter across the ign s/w terminals and check, switch on / off numerous times and look for deviations in the on reading. i no longer have a key fob on my switch key , i think this accelerates switch wear.

My initial thoughts are ignition switch as well. Can you bypass it and go for a ride? See if it still occurs.