The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: Stuie on 14.11. 2020 09:24
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Hello everyone.
This is my first post, apologies if its been asked before but I'm restoring a 1947 a7 rigid, I took the dynamo off yesterday to find that's its a e3l rather than an e3h as it should be, can anyone tell me what the difference between those two is?
Thanks
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Hi Stuie, The difference is in length and wattage output. The early A7's had the shorter E3H that had an output of 45W where as the later ones from 1949 had the E3L which was longer and had an output of 60W. The early A7 had a a different drive side front engine plate that covered the end of the dynamo but when they introduced the E3L they put a hole in the engine plate for the dynamo to stick through. Here is a picture of what a early drive side engine plate looked like.
Now how about posting an introduction and perhaps some pictures of what your restoring. I have had a 48 and 49 Long Stoke A7 and learnt a fair bit about them during their restoration.
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Replacing the E3H with an E3L was a common and some would say vital modification to many mortorcycles, my B31 included. A 45 watt dynamo is just a bit puny for modern road conditions where riding with a headlight on is pretty much essential. I would strongly advise sticking with your E3L.
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Thanks for the replies gents,
Perhaps I'll stick with the e3l for now then. but I think I'll track down an e3h and cover for the sake of originality, even if they live on the bench next to it
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just FYI i put a few pictures ion the introductions section.
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I agree that sticking with the later E3L makes sense. Finding a E3H will not be difficult but trying to track down a correct engine plate may take a while as they are a bit like rocking horse poo. At least you have the picture so you know what you are looking for.
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The timing side plate is a right sod to get out, so more often stays with the motor. The drive ones are loose fit and make the bid for freedom. The later E3L hole in the middle plates are very similar to the later plunger type, but with differently positioned holes. When searching, plunger plates have a small triangle reinforcing plate spot welded inside around the front top hole, Longstroke plates do not have this. The small joining spacer is the same for all types of pre S/A frame.
E3H domed cover type is distinctive but a rare Unicorn Part these days.
Swarfy.