Signal Generator coils 650 vs 550

[Guest]

Hi Guys,

I've had some progress with my signal generator problem, would appreciate it if anybody can tell me if my assumptions are correct.
To recap, my 650 katana donor bike(s) are still in pieces, and I'm still a long way from starting the assembly work.
I don't have a 650 signal generator plate, however I do have a 550 plate. (One of the donors was a 550 with a 650 top end).
the 550 seems to fit on the 650 crankcase, and the position of the magnet on the 650 advance mechanism seems to line up correctly with the 550 pickups.
It also seems that the 550 wiring can be changed to suit the 650. (Basically, the common from the 2 pickup coils just needs to be earthed to the signal generator plate rather than going off to the ignitor circuit as it does on the 550).
So far so good.
However, the specs for the pickup coil resistance on the 550 says 60-80 ohms (over one coil), while the spec for the 650 says 250-360 ohms (over both coils).
To me, this sounds as if the 650 pickup coil has approx twice the number of turns as the 550 coil (assuming the wire diameters are the same). This then makes me worry that the 550 pickup coils will not produce enough of a pulse to fire the 650 ignitor.
I've tested the 550 coils and they seem to be fine.
If I am going to need to source another signal generator plate then I'd better start now (They are not easy to locate in South Africa!)
Any advice gratefully accepted!
Cheers,
Ian

[tom203]

You need the 650 signal coil setup to fire the 650 ignitor - they are matched and live happily together. They pop up on eBay regularly.

[IanW]

Thanks

You need the 650 signal coil setup to fire the 650 ignitor - they are matched and live happily together. They pop up on eBay regularly.

Thanks Tom, duly noted.

In fact I've found one on ebay for a good price, and it's on its way.
Just need to keep my fingers crossed that it actually arrives, not a guarantee over here I'm afraid.