OK boys and girls:
A Pulsar N12 electronic dizzy is already the right diameter and length to fit a Mini. No shaft cutting or body machining is needed.
For fitting one to an A+ motor, read this thread, then the other one in A/A+ Mods forum. viewtopic.php?t=11178
1. First get your Pulsar dizzy. Comes off an N12 Pulsar, 1600cc, late 80's.
Part Numbers: stamped on dizzy body near the vacuum canister-
Pulsar auto- D4R83- best on 848-998-1098 <edit> will work on stock 1275 but D4R85 is better.
Pulsar manual- D4R85- best on modified 1275 up, big cam, carb, head etc (IMO)
<edit> the auto has 16* dizzy mech advance & the manual has 12*
Double these numbers to get crank advance degrees.
2. Get an old Mini dizzy- any old thing will do. You just need its drive dog.
3. Remove pin from Pulsar drive dog with a 1/8" pin punch and BFH.
4. remove pin from Mini drive dog with a 3/16" pin punch and BFH.
5. Remove the Pulsar drive dog. Put Pulsar dizzy in a vice on a bench drill, clamp the shaft and carefully enlarge the pin hole with a 4.5mm drill, then a 3/16" drill. Keep it straight and square..
6. Put the Pulsar thrust washer on the shaft, then slide the Mini drive dog on. The pin holes may not line up- if so you would then need to remove 1mm (.040") approx from the top (flat) face of the drive dog. Ideally you want .005"-.010" end float when it's assembled, with the thrust washer in.
NOTE: fit it so the rotor's brass strip is pointing at 1 o'clock, and the `drive key' is below centre of Mini drive dog.
7. Run the 3/16" drill thru the dog and shaft to ensure alignment. Fit the Mini pin.
8. Put the dizzy in a vice, holding it by the slotted Lug. Then get a hacksaw and cut the lug off.
9. The flange of the dizzy body is already the right diameter to fit into a Mini clamp plate. File or linish the part where you cut the lug off of, so it matches the rest of the flange. Use a clamp plate to check when it's right.
10. Use the Pulsar coil. It is 1.5 ohm, so if you wanted to you could use a Bosch GT40-R coil instead. But no need- mine fires .040" plug gaps to 8000 rpm...
NOTE- although it may be marked as a resistor coil NO RESISTOR IS USED with this dizzy.
Pulsar coil primary leads are long enough that you can put the coil on the inner guard if you want (keeps it dry)
<edit> fixed typos, added more detail..
