Dynamo doesnt fit

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Johnlukes
Posts: 3
Joined: Sat May 19, 2018 12:11 am
Location: West glamorgan UK

Dynamo doesnt fit

Post by Johnlukes »

Apologies if this has been asked previously, but I cant seem to find a solution anywhere.

My recently purchased bike has needed dynamo attention. The dynamo fitting doesnt seem quite right, firstly I want to check that the Lucas E.3.A.R A.0.5-1 is the right dynamo for a 1956 G80CS. The dynamo has the spacing strap screwed on, and the drive sprocket aligns nicely with the drive chain, but is there really no seal between the dynamo and the chaincase?
The previous owner had bodged up some kind of petrol pipe with a wire passing through it and twisted at each end to form a circle and a crude oil seal. For the life of meI cant see a picture of what the original fitment looked like. Can anyone help me with a picture or a tecnical drawing or details of any parts that I am missing please.
Thanks in advance
John
swansea UK
SPRIDDLER
Member
Posts: 8542
Joined: Wed Sep 01, 2004 1:00 am
Location: WEST SUSSEX UK

Re: Dynamo doesnt fit

Post by SPRIDDLER »

Welcome, John.
If you look at page 49 of the spares list here:
http://archives.jampot.dk/book/Spares_l ... _G80CS.pdf
it shows the dynamo as type E3N-L-O but (from a clouded memory) I think your E3AR will fit and be O.K. although it may have a lower output (36watts) than the E3N.
Regardless of the fact that your dynamo has a spacing/alignment strap fitted you must check that the dynamo chain and primary chain run clear of each other or serious damage will result if they clash.

and
on page 33 you will see the pressed steel chaincase. There is no seal on either the dynamo or the gearbox shafts as both have to move within the chaincase apertures when adjusting the chains. There are steel guide pressings on the inner chaincase which divert oil around the apertures.
Some owners have made up a sliding felt disc (usually because their bike is used off-road) which fits over the dynamo and gearbox shafts, more to keep water and dirt out of the chaincase rather than to keep the oil in it.
I, and most owners have never found it necessary to add a felt seal.
If the primary chaincase is overfilled then it's more likely that oil will exit the shaft apertures. The oil should just touch the bottom run of the primary chain at its lowest point.

There is much more help available. Your time as a Guest is limited so it would be a good move to join the club - the memberships' subs finance these Forums!

P.S. The steel chaincase halves have been notoriously difficult to seal. You can check the function of the dynamo before fitting the outer chaincase and adding the oil later (provided that you keep your trousers and shoelaces clear of the chains!).
There is now an improved seal available from Club spares:
http://www.amoc-parts.com/store/comersu ... duct=23441
'There is a tide in the affairs of men
Which taken at the flood............'
Johnlukes
Posts: 3
Joined: Sat May 19, 2018 12:11 am
Location: West glamorgan UK

Re: Dynamo doesnt fit

Post by Johnlukes »

Thanks for the very quick response, the info is extremely helpful, based on this I have already ditched the previous owners attempt at sealing the dynamo hole in the chaincase..

Hi cbranni
Would love to take you up on the offer, but I don't seem to be able to message you. My email address is johnlukesuk@gmail.com if you could send me your email address I will reply directly..
Cheers
John
bjorn
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Joined: Mon Jan 01, 1990 12:00 am
Location: NORWAY

Re: Dynamo doesnt fit

Post by bjorn »

Spriddler:

"and
on page 33 you will see the pressed steel chaincase. There is no seal on either the dynamo or the gearbox shafts as both have to move within the chaincase apertures when adjusting the chains. There are steel guide pressings on the inner chaincase which divert oil around the apertures."

This is correct as regards the lack of seal for the dynamo, but the CS inner chaincase has a sliding seal and is different from the standard bikes. Refer to page 32 Front Chaincase

Bjørn
Johnlukes
Posts: 3
Joined: Sat May 19, 2018 12:11 am
Location: West glamorgan UK

Re: Dynamo doesnt fit

Post by Johnlukes »

Hi Bjørn,

That's really interesting, and of course a shame there is no photo of it on the next page. Now where the heck would I get one of those, or at least one to copy?
I would think that they added a seal to the CS model as it was expected to encounter a bit more mud and water being the competition model :)

John
cbranni
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Joined: Sat Oct 09, 2010 9:17 pm
Location: ABERTAWE UK

Re: Dynamo doesnt fit

Post by cbranni »

Email sent John

Colin
only dead fish go with the flow
SPRIDDLER
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Joined: Wed Sep 01, 2004 1:00 am
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Re: Dynamo doesnt fit

Post by SPRIDDLER »

bjorn wrote:Spriddler:

"and
... but the CS inner chaincase has a sliding seal and is different from the standard bikes. Refer to page 32 Front Chaincase

Bjørn
Thanks Bjørn. I wasn't aware of that, not having worked on a CS, and my concentration does tend to drift a bit when bashing out a 'generic' reply. :oops:
'There is a tide in the affairs of men
Which taken at the flood............'
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