TOPIC:

I was just reading through my service manuel and I see that the coils are listed as having 4.0 OHM resistance. Im wondering if this is correct and if the 3.0 OHM coils will work without burning out ? Does anyone have any insight into this ? Are the stock coils marked with the OHM resistance ? Thanks for the help. Wayne

Good queston. I got around 5.1-2 OHMS on my 650 coils and 3.2 on some 550 coils. I think that I did it correctly.???

I just did a search in the archive and found that others had the same question and that it might of been a miss print in the manuel. I'll have to do more research and maybe the wiring upgrade, along with new coils from Z1 enterprise and the dyna ignition. Thanks for the reply Wayne

The 3 Manuals I have for the 650s all list the Primary winding resistance (R x 1 measured between the yellow/red wire and the green or black wire) as 4.0 ohms. And the Secondary winding resistance (R x 100 measured between 2 spark plug wires, from the same Coil)as 23K ohms.

The early 650's used 4-ohm coils. The 550's used 2.5-ohm coils. Your ohm-meter may be off by 1 ohm.

The 3-ohm coils will work with points, but will shorten the life of the points. By how much? Not sure.

3-ohm coils will have roughly 30% more amperage.
30% more amperage is roughly 70% more heat dissipation in the points (compared to 4-ohm coils).

This is just a little joe blow multimeter. It goes 200,2k,200k,20m set at ohms. Along with the various other setting in DCV,ACV,BAT,DCA, etc. I don't know much about using this thing, but figure that 200 OHMS is the proper setting for this thing. I just test the coils by themselves off the bike. I get consistant readings, but will concede that a 200 OHM setting wouldn't be that sensitive............Oh ya, this was interesting.

www.motorcycleadventuremap.com/accel.htm