Forum

[Dunc]

Hi all,i am a new member and posting for the first time.

Restoring/building a 1954 500 twin.Planning on using a srm goldie mag converted to electronic ignition with a double lead coil.But having trouble sourcing the mag base/mounting plate.Hitchcocks have an image of the offending! part,but none in stock.

https://flic.kr/p/2ewyW5U

If I can't find one then im hoping that someone here could give me the dimensions so as to get one made.

I have set up a plea in the wanted section.

[Tim NZ]

I am trying to understand what you are doing and why? It seems like a lot of work, to me, and a bit unusual...


What is wrong with your original dynamo/distributor?


The BSA MO1 style mag is not mounted exactly the same as the RE dynamo/distributor. The MO1 is held down onto the crank case with two straps. Base shims were used to accommodate correct timing gear pinion meshing. The shaft 'oil-seal' was wave washer pressing down onto a felt ring, which was 'loosely' able to accommodate the gear meshing adjustment.


Does your engine have a slipper fitted to the dynamo chain to tension it? The original dynamo base cradle has provision for a modicum of chain tension adjustment. But for all intents was directly attached to the back of the engine and left the drive chain free to flail around.


When RE dropped the coil ign set up and changes to a MN2L Mag/dyno in 55, the new unit was mounted directly to the rear of the timing chest with provision for limited chain tension.


Would not that be a potentially better set up for you than modifying the SRM unit, which rotates in the other direction..?


What dynamo are you using?

[Dunc]

Building the bike from 2 basket cases(basically one frame and engine and another frame with wheels and tank!)So have no electrics at all.I think the 54 was dynamo with distributor on top,listings for 55 was the magdyno.Friend of mine who runs a business building and repairing british classics assures me we can make it work.All my previous bikes had alternators so havnt had experience of mags and dynamos.Theres no slipper,whether dynamo or magdyno the base plate had an oval slot that located on a stud so to move fore and aft.Won't be altering anything so can revert back to a dynamo set up.I thought the modified mag would work in either rotation..........but will enquire.The rational is to end up with electronic ignition.

[Adrian]

Before you cut an paste the following link into your browser, make sure you're sitting down when you read the price!



You can get a BT-H electronic magneto (using CDI technology) in various types, INCLUDING the twin cylinder version of the magdyno, though this one will need you to buy a dynamo (or the Alton AC generator which is a direct replacement for the Lucas Dynamo) separately.



https://www.bt-h.biz/md2r---magdyno-twi ... o-18-p.asp



A.

[Dunc]

Have already got the mag and dyno...........and have just tracked down the mag base plate,for a tenner!, from a guy who recons mags and dynos. happy days