Magneto chain Alignment

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Columbo John
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Joined: Sat Jan 15, 2022 5:51 pm
Location: Bedfordshire UK

Magneto chain Alignment

Post by Columbo John »

I've been assembling my '55 G3 project making studs and spacers as I go along and earlier today after making the magneto mounting bracket studs and spacers, I trial fitted the exhaust cam and sprocket and spacers and offered up the magneto chain.

Unfortunately, something is seriously out of alignment! What am I missing? The magneto mounting bracket sits outside of the of the engine plates with 1 9/16" spacers on the right hand side as per the info in the Jampot Archive and there is no other holes in the bracket that could be used to botllthe magneto to?

Any ideas? TIA John. :beer:
20230226_170127.jpg
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Columbo John
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Posts: 39
Joined: Sat Jan 15, 2022 5:51 pm
Location: Bedfordshire UK

Re: Magneto chain Alignment

Post by Columbo John »

Well I appear to have answered my own question. Whilst the mounting plate only has one set of holes, the magneto itself has two sets!

Moving the screws to the other mounting holes moves the magneto a lot further out. I will try it with the chain on when I get home later.
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clive
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Re: Magneto chain Alignment

Post by clive »

You are up too early for a reply before yours but it sounds like you have cracked it. The SR1 mag was used on stationary engines as well as bikes and so some of the bodies may have had additional holes to allow a different alignment.
clive
if it ain't broke don't fix
Columbo John
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Location: Bedfordshire UK

Re: Magneto chain Alignment

Post by Columbo John »

clive wrote: Mon Feb 27, 2023 9:02 am You are up too early for a reply before yours but it sounds like you have cracked it. The SR1 mag was used on stationary engines as well as bikes and so some of the bodies may have had additional holes to allow a different alignment.
I haven't had the chance to assemble everything in place to be 100% sure that I've cracked it but it certainly looks right. :thumbup:
56G80S
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Re: Magneto chain Alignment

Post by 56G80S »

Just a thanks to the original author and for the photo. I did a "dummy run" and was lucky to find that, with the mag right at the edge of the platform, my straight edge showed ideal alignment of the sprockets This was different to how it had been previously, my fault for not taking care when swapping magnetos around.

That probably explains the slight witness marks behind the ATD where it had been catching the rear chaincase. That in turn may well have been the reason why the ATD wasn't returning properly to retard!

Thanks again. The Search function is soooooo useful.

Johnny B
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