ps What you are trying to achieve is quite an expensive modification.

You will need to find a way of mounting the alternator somewhere on the engine and then try to run a belt from the end of the crank to the pulley housing on the alternator. You would need a way of adjusting the belt tension.

I guess you may need to machine the crank and cut the primary chaincase. That's a lot of work. I wouldn't know how to fit a pulley on the M20 crank.

Personally, I would spend the money on getting your existing dynamo reconditioned and the headlight reflector re-silvered.

You can then choose if you want to run a 6 or 12V system. The downsize of 12V is the plates in the battery are very small and can deteriorate very quickly.

If it was me, I wouldn't do it.

email (option): sacombsashtrees@hotmail.com

Hi Micheal

Just Googled what you are looking to achieve i.e. somehow turning the rotor not from the end of the crank but from where the dynamo rotates.

I haven't seen it done, but if someone has done it on an expensive Vincent.....then maybe!!

Regards

Pat

ps I would still go down the route of a reconditioned dynamo and re-silvered reflector even if I could afford a Vincent!

email (option): sacombsashtrees@hotmail.com

Hello Michel,

The Kubota alternator is a permanent magnet alternator,
Much like the "Alton" and the "Powerdynamo" are.

The good thing about it , is that you do not need the stator coils, so it is much compact, with powerful
Permanent magnet, but on the other side, it always has some resistance for turning, whether the battery needs charging or not.
Whilst traditional alternator, like the dynamo, rotate smoothly when not charging is needed.

I saw at the past an E3L Lucas with a "window" cut on the side, (on the "width" of it, on one side)
The internal coils where gutted, and replaced by a small pulley.

At the time of putting the "dynamo" together, a belt inserted from the "window", the internal axle
(What was previously the armature) inserted, with the belt now on the pulley,
And after all was mounted, the other side of that short fan belt, drove a small Suzuki alternator
Which was mounted above the dynamo.

I was quite a while ago.
Wish I had taken a picture…

Cheers,
Noam.

Alton do an alternator for bikes like the BSA A10. It is the same size as the dynamo and an easy fit.

Only real difference is it is belt driven.

I just can't imagine where you would easily fit an alternator for something like M20s.

email (option): sacombsashtrees@hotmail.com

Thanks a lot to you all.
I'm located in Israel. These small alternators are also fitted on other engines and generators.
I will think it over again.
I intend to take the drive from the magneto.
I will post as soon as something will proceed.

Hi Patrick,

"Alton" also does an alternator for the M20
Which is a direct replacement for the "Lucas" and driven the same.

I have one of them on a WM20 ad it works great, only add some noise.

Noam.