Mk3 electric start

Thomasa said:

I have a drawer full of assorted Norton E-start parts, including a Sportster starter armature -- it will not work. What you want is to use the Norton armature in the 4-pole Prestolite Sportster starter field assembly. After you assemble that and get it clocked properly and working, you will find that you need to use larger cables from the battery and relay to the starter. After you do that, you'll find that the battery will not provide enough oomph to start the motor. A Goldwing 1500 battery can be made to fit, only just. It's a challenge to get it in but it can be done. After all that, you'll find that the torque-limiter/anti-backfire device won't stand the torque and makes very nasty noises. You can tighten the nut on the device a little to reduce this tendency but if you go too far it will destroy the sprag clutch. The spec is 50 ft. lbs. I set mine to about 58-60 and it seems to work, mostly. Sometimes it still makes the nasty noise but then I'm confident that it's releasing as it should. So if you want to go down this path, have the Norton armature rewound. In the end it's quite satisfactory but it was a many year process to get here and I worked in a Norton shop where we removed E-start assemblies at owner's request, trashed them and blocked off the starter hole. That's where I got all the parts.

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worntorn said:

Mine has always started nicely on a standard battery. Right now there is an undersized cheapie battery in there, a $28 ytx 12 ebay special, only 10.5 ah. It starts ok on that.
The cables are heavier than stock and the four pole conversion was done in the 80s. Chinese sprag in place since 2017.
The anti kickback device has not given any trouble in the 20 years I've been riding the bike. Someone might have set it up when the four pole conversion was done about 40 years ago.

Glen

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