Lost spark on one cylinder (PMA/Pamco w CAP)

[calebxs]

Hi Guys,

Looking for some insight on an electrical issue. I'm running PMA/PAMCO with capacitor on a 72 XS.

Bike was running fine, then lost spark on one cylinder and blew the fuse. I haven't touched the carbs (or anything else).

Between blowing the fuse and starting the bike again I re-checked all wiring, clipped and reattached spark plug boots and connection to coil, cleaned up any questionable connections and re-grounded everything (sanded bare metal contact surface for grounds). Bike runs and idles fine on one cylinder. I'm hoping someone can give me some advice on diagnosing what is wrong.

Am I wrong to assume that the PMA, regulator and cap are all fine? I feel like it could be the coil.

Thanks!

 

[figure8]

I'll give my I just woke up still groggy thought, I don't think Pamco coils go half bad. Check coil wire and connections to coil and spark plug....put a new spark plug in as well.

 

[fredintoon]

Hi caleb,
not familiar with PMA/Pamco but if the Pamco is a wasted spark (fires every 360º) system,
swap the plugs & plug wires over to the other cylinders.
If the problem moves to the other cylinder along with the plug/wire swap, it's ignition.
If it don't, it's carbs.

 

[5twins]

Yes, a single coil with dual outputs (plug wires) either fires both or neither, it won't fire just one. Problem should be in the plug wire, plug cap, or plug on that dead side. I would swap the plug leads from side to side at the plugs (leave the plugs where they are). If the dead cylinder switches, it's the wire or cap. If it doesn't, it's a bad plug.

 

[calebxs]

(Also running Iridium plugs)

Thanks for the input so far, I really appreciate it.

Assuming one of these components (boot, wire) is bad would you recommend I reorder from Mikes? I know they sell their wires and boots as "high output" and bundle them with the ignition, but I'd love to find them locally can get this thing back on the road.

Thanks again! So helpful.

Caleb

 

[figure8]

Not necessary to get from Mikes, you can get it local:

 

[calebxs]

Any particular specs on the wire and boot?

 

[pamcopete]

calebxs,

Check your cap voltage at 3,000 RPM to be sure it is not high, like > 15 Volts. You could have two problems here.