Weak spark

My '73 Roadster is not currently running. It has a brand-new mikuni and a brand new boyer. Both of these additions were working fine, but one day the engine flat quit on me while coming into town. I cleaned the jets since the plugs were pretty fouled and they were a little clogged.

The engine was behaving like it had a vacuum leak, which may be the case, but now I can't get the engine to fire up at all. I charged the battery and pulled the plugs to see if they were firing. They are, but it's not a big fat blue spark like I would expect. The boyer measures 11.5 V at the box. I accidentally touched the head while kickstarting it and got a shock, but not much of one, like I would expect if it were getting a good spark. It just seems like I'm not getting enough fire. I sprayed a shot of starter fluid in the chamber and it did want to fire up a little.

Is there any way to see if I'm getting an adequate spark? I know the ignition is new, but could I have a bad stator or something else? What should I be looking for? Any help appreciated.

make sure you have a fully charged battery boyers need a strong battery. also check your wiring make sure you have a good ground on the frame down to bare metal .I remember those boyer days theyed say check your battery and it was always the battery M.c.

Also check for a loose wire at the pickup plate. Boyers are notorious for having those bullet connectors vibrate loose or break wires inside the boot. These connectors should be soldered rather than crimped, and arranged inside the cover so that the connections aren't stressed.

Mine died on me back in October, luckily near the end of a 100-mile ride. Intermittent rough running went to dead. After checking everything, I opened up the timing cover and found one of the wires had broken cleanly right at the crimp. It worked as long as the wire was in contact with the bullet, but any vibration caused it to separate.

Intermittent spark will foul the plugs, as you're still getting gas in the cylinder, just not lighting it every time.

If you got shock off the motor I would guess you've got a bad motor earth. There's one on the top of the head and another on the gearbox plates. Powder coating or thick paint will increase resistance.

Check the earths out and try a new pair of plugs as carbon fouling can be hard to get off.

Cash