ignition boxes, are they interchangable?

[newmaac]

Hi folks,
JTodd is looking for an ignition box for his bike. The existing box is marked 4RO-10.
I have a couple spares that are marked 2H7-10.
Can anyone tell us if these are interchangable?
Thanks,
Mike

By the way, his is a 1981 Midnight Special.
Mine are from a 1979 F, and a 1980 Midnight Special.

[sambodie]

It's my understanding that they are not interchangable, but I can't say this with 100% confidence.

[skids]

Re: ignition boxes, are they interchangable?

They are not interchangable. The 81 models had a different advance mechanism than the other models and the 4ro-10 unit did the spark advance. Also, the 81 did not have a ballast resistor. It is best to find another 81 type black box.

Originally posted by newmaac
4RO-10.
I have a couple spares that are marked 2H7-10.
Can anyone tell us if these are interchangable?
Thanks,
Mike

[newmaac]

Got it. Thanks guys.
JTodd, it sounds like you have it covered now anyway. Good luck.

Mike