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Wiring hole position on E3L dynamo end cap

Posted: Sat Jun 06, 2020 2:07 pm
by Nickfrank
I have a person in Canada who has end caps (something that Draganfly has been out of stock on forever). He has a couple of different types with the mouse hole as he calls it (rubber grommet) where the wiring enters the dynamo, at a different position once the dynamo is rotated on the timing chain and tightened up.
Would anyone know the right cap for a '58 Huntmaster? He apparently has caps with the hole at both the 5 o'clock and 11 o'clock positions.
Thanks, Nick.

Re: Wiring hole position on E3L dynamo end cap

Posted: Sat Jun 06, 2020 4:11 pm
by pete.collings
The cap with the wiring hole at 11'oclock is the correct one for a 1958 Huntmaster, there is a "church door" shape grommet that fits into the hole, that can be a bit harder to find that the type used for the earlier plastic end piece. This orientation allows the dynamo cables to be routed up the frame downtubes.
The 5'oclock end cap is used with the magdyno singles, not sure if this also suits a Fieldmaster?

Re: Wiring hole position on E3L dynamo end cap

Posted: Sat Jun 06, 2020 5:36 pm
by Mick D
Hi

From my research, I think the end caps, (200902, 200918), with the church door grommet were not fitted to Huntmasters - check out the Lucas documentation.

Having said that, I have a 20036A, (BSA A10 dynamo), fitted to my 58 Huntmaster and the loom outlet is at 0700 which leads itself to routing under the engine and up the down tube.

Regards Mick

Re: Wiring hole position on E3L dynamo end cap

Posted: Sat Jun 06, 2020 8:51 pm
by pete.collings
I have rechecked the Lucas documentation I have (Full catalogue 1936-57), and page E12 shows dynamo 20036 (one piece end cap) suiting a 1954-57 Huntmaster. However, an Ariel specific catalogue for 1958 shows 20010, so perhaps the original fitting was this, but it was uprated to the later format of dynamo when this was available.
In any case, either is suitable for a 1958 Huntmaster, I an not sure what to recommend if absolute originality is desired.
I have to say, I have never seen a one piece end cap with the cutout at 7'oclock in relation to the bulge, maybe this is a modification that someone had made for a preferential cable routing?

Re: Wiring hole position on E3L dynamo end cap

Posted: Sun Jun 07, 2020 7:11 am
by Mick D
Hi Pete

The cut out on my end cap is at 05:00, (if the bulge is considered to be 12:00), when the dynamo is fitted and adjusted for chain tension the outlet is at 06:30.

Dynamo End Cap.png
Dynamo End Cap.png (185.21 KiB) Viewed 449 times


Thanks for the pointer to E12, I was using the 1958 Lucas Equipment catalogue as the reference to my, and the OPs bikes but perhaps there was a grey area during changeover and my dynamo is actually original and not a replacement from an A10 as I had thought - bonus :)

Regards Mick

Re: Wiring hole position on E3L dynamo end cap

Posted: Sun Jun 07, 2020 11:39 am
by pete.collings
Hi Mick

Thanks for the photo, I think we have a slight difference in what is considered as the 12 -6 axis of the endcap. In my mind, what you show is a cutaway at 11'oclock, which is what I would expect for a Huntmaster dynamo, with the base of the bulge at 6'oclock.
As BSA built all the Huntmaster motors on Ariel's behalf from around 1955, they would have presumably used the same dynamo model as the A10/Rocket models.
As an aside, I have some of these dynamos (Huntmaster/A10/Rocket) available, rebuilt but not fully reconditioned, all have motored OK but are not road tested. As I am not doing any autojumbles due to the pandemic, if anyone is interested I can be contacted via my listings in the Parts For sale/Wanted section, at the top of the listings of that Forum section.