New Rotor = Weak Spark?

[xander18]

The only thing I've done to my 80 Special since winter was an alternator rotor off of a spare motor I had kicking around. I've done the ignition coil and my pick up coil tests okay (700 and 635). Could it be the rotor? Is there a difference from year to year on how the rotors 'talk' to the pick up coil?

Thanks
x

 

[xander18]

I changed rotors and it worked. The rotor that I did have on the bike is a slightly different casting, missing some numbers. Must have been a cheap knock off.

 

[gggGary]

A different member reported similar issues turned out the knock of rotor was thinner so the magnet was too far away from the pick ups to create strong enough signal.

 

[xander18]

That's what I assume it was. Don't know what the deal is with that other rotor. Maybe I'll examine the stator off of the motor I pulled it off of, maybe they were sold as a set.