1955 fastwin ignition concerns

[codykoke]

I have a 1955 fastwin im trying to get running. On the first attempt i had spark in only one cylinder. I took it apart and checked resistance from plug boot to ground, I found one had no continuity so i Fixed it by connecting spark wire to coil and then the both sparked and had 4.5 k ohms in both wires. Well after I put it back together I fueled her up and it backfired on me. I checked for spark again and no spark in same wire as before so i checked resistance again and still have 4.5 k ohms in both wires. I don't get it, could there be a short somewhere causing spark to ground but still have proper resistance. I apologize for long post but wanted to describe process.

 

[SeaKaye12]

Re: 1955 fastwin ignition concerns

Are your coils new?

 

[codykoke]

Re: 1955 fastwin ignition concerns

They have been replaced be
fore i got the motor and are mallory brand i believe

 

[Chinewalker]

Re: 1955 fastwin ignition concerns

Backfire typically means the plug wires are reversed. FRONT coil fires the TOP cylinder...

 

[codykoke]

Re: 1955 fastwin ignition concerns

I've got the front coil on top cylinder. I was able to get spark back in both cylinders, but still backfired and won't start. Correct me if I'm wrong but is backfiring when it fires before the piston covers up the intake holes?if so is there a way to adjust timing

 

[Chinewalker]

Re: 1955 fastwin ignition concerns

If the points are set at .020 with the rider right at the crankshaft keyway, then your timing is set. Nothing else to adjust...

Is your crankshaft key intact? A sheared key will throw off your timing...

 

[codykoke]

Re: 1955 fastwin ignition concerns

The cam is on the key. And the points are set it just seems to either fire properly a co
uple times or backfire

 

[codykoke]

Re: 1955 fastwin ignition concerns

I just noticed 2 little holes on the left side of the carb it looks like there should be plugs in them but i don't know.

 

[Chinewalker]

Re: 1955 fastwin ignition concerns

Those are vents - don't plug them...

 

[codykoke]

Re: 1955 fastwin ignition concerns

Oh ok. Well I've decided to rebuild the carb again. I didn't have the filter in so maybe a jet clogged and is causing it to run to lean.