E3L dynamo issue

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g5wqian
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Joined: Wed Nov 18, 2015 7:43 am
Location: wiltshire
Location: near swindon wilts

E3L dynamo issue

Post by g5wqian »

hi all;
my dynamo stopped charging on my AJS 30 twin and so took it off to investigate .

initially had 1/2volt out on tickover and 3volts at 2000rpm .

i have taken it apart and have a fair amount of oil residue inside , the brushes are good but holders and brushes have oil and dust deposits on them , i will clean it all up and replace bearings and seal and i guess the oil has got in from the seal end over time .

possibly it had not been functioning properly due to the oil on the brushes/holders and armature , plus in the air gap between armature and everything else for that matter .

i saw that when i removed the dynamo it had an o ring on the end between it and the timing casing and was also sealed with silicone sealant , is this normally what i would find , is the o ring an original part or a later addition or should it have a paper gasket instead , or nothing .

i have the lucas manual for the dynamo but its 1953 and so i dont know what they did later on as mine is 1956 model .

thought id ask about any issues common with the dynamo whilst i am awaiting the new bearings and seal for it as there might be some usefull tips you lads may have for when i put it back together and re install it .

thanks
ian
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Stuoyb
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Joined: Tue Jul 27, 2004 1:00 am
Location: BEDFORDSHIRE UK

Re: E3L dynamo issue

Post by Stuoyb »

The “o” ring and sealant are an attempt by someone to seal the joint between the dynamo and timing case.
The factory installation was a cork gasket (014141) as shown in the parts book.

http://www.amoc-parts.com/store/comersu ... duct=21075

You just need to be careful when you install the dynamo so that you don't damage the cork and then use the draw stud to pull it fully home.
Groily
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Joined: Thu Jul 04, 2002 1:00 am
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Re: E3L dynamo issue

Post by Groily »

An O ring and silicon is often better than the correct bit as it's a notoriously difficult joint to get oiltight. A lot of twins have a tell-tale streak or worse just below the dynamo . . .
petert120r
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Location: POWYS UK

Re: E3L dynamo issue

Post by petert120r »

Also, be careful with the draw stud as it's easy to strip the thread where it enters the dynamo. The draw stud isn't really man enough to pull the dynamo tight - I use a piece of wood like a broom handle to lever the dynamo snug to the timing case and then tighten the metal strap securing the dynamo to the crankcase. Fit the draw stud nut last and don't over tighten it.
g5wqian
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Posts: 220
Joined: Wed Nov 18, 2015 7:43 am
Location: wiltshire
Location: near swindon wilts

Re: E3L dynamo issue

Post by g5wqian »

thanks for all your replies , much appreciated and i learn something everyday .

i shall certainly use all your tips when i put it back together again .

thanks
ian
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