<-=- Club Bevel Heaven -=->

Hi Guyz.
My 250 Diana loses spark when hot. Replaced coil, condenser etc. to no avail. Also had flywheel remagnetized. Anyway, looks like the flywheel coils are breaking down when hot. (No surprise there since they're fifty years old.) Anyway, before forking out the big bucks for one of the modern flywheel setups now available, I thought I'd try to re-wind the original coils or find someone who can do that.

Has anyone out there tried re-winding their own coils? If so, any advice greatly appreciated. Also, can anyone advise of checks I can do with my VOM to test the coils for continuity, resistance, etc. before I start to mess with them?

I have the original manual however it has no info on troubleshooting the coils. The coils are now off the bike.

Thanks in advance

I have been through this on many of my singles!

Best thing is to check the AC output, in terms of Volts, when cold and then re-check when the engine is hot. Even with a so called re-magnatised rotor I found that the voltage dropped off to about 4vAC, which means that you are draining the battery. If you are running the magneto setup (with the AC ignition coil), you will just loose spark.

I had two of the generator coils from my 98 pushrod motors re-wound and still I had problems once the engine got hot. These cost me GBP50 per go.

It appears that heat into the rotor seriously reduces the level of magnatism, leading to a loss of spark.

I now just fit a Electrex generator and convert to 12v, 120w and forget about the problem.

Chris

Thanks Chris. Looks like I can't get away with being a cheapskate after all. I'll do the full upgrade.