Forum

[Adrian]

There are no auto advance/retard units currently under that listing. It does show an impulse starter, which was a spring-loaded rotary device to flick the magneto over faster when hand cranking some stationary engines fitted with the SR1 magneto, also some JAP rotovator engines had them. A.

[mauri]

this is the exact one(47556) your looking for, you can see that the advance unit and pinion are one unit.

held on by one central bold which also serves as an extractor when you would want to remove the ATD.







at the back there is a internal taper that fits on the external taper of the SR1 or any other of the lucas magneto’s, magdyno’s.

[papatom]

Yeah, thats the one with a 40T gear.
Got to ring Tony Cooper to see if the ebay listing for an AJS ATD can be refurbed for mine. Please keep all ideas coming. Cheers. Tom

[mauri]

if can do it, so should anyone else.



in this case i used the same model as on sale at the moment on eBay.

[John M]

Your bike will run quite happily without an advance and retard on your SR1, however if your bike has a crank mounted generator an Indian distributor housing and coil ignition would probably be the simplest option.

[Adrian]

If you do go down that road, the later 500 Indian Bullet contact breaker drives (I know we call them distributors, but on a single there's no second cylinder to distribute the spark to!) are better, as they use proper bearings rather than bronze bushes. A.

[papatom]

Hi mauri. Rang Tony Cooper, magneto refurbisher, who has instructed me NOT to get the atd on ebay as it/he cannot adapt it to my sr1 as I do not have an english rotor or the pinion. John M/Adrian, I am liking the sound of the mentioned alternative, however, not yet being that savvy, I am finding it difficult to follow what I might need, therefore unable to cost it out etc.. Could you please enlighten me if that's ok. Again, thanks to everyone for their input. Cheers.
Tom

[mauri]

the pinion is made by modifying a standard enfield idler pinion.



i am a bit at a loss in what you mean with the rotor?

the pinion(rotor?) is FIXED to the ATD its NOT a separate part.



form your post i understand you already have an SR1, the only thing needed now is to adapt the idler pinion to the ATD.

ones you have this pinion its a 10minutes job to take the ATD apart, drill the 4 old rivets, put 4 new rivets in and put it back together.



thats all there is to it.

[Adrian]

Papatom,



with Mauri's latest post insisting the ATD conversion IS viable, you may still wish to pursue that futher. With that in mind I still offer the magneto options as a fall-back position, but I'll let John M explain further about running an SR1 on fixed full advance, this isn't something I want to try for myself.



So do you want to keep the Lucas SR1 because of its originality, or because you think (rightly) that it's one of the prince of darkness' better pieces of kit? Or would another form of magneto ignition suit you equally well?



First option (all of these assume you can't find an ATD), fit a different magneto. The gold-plated option would a new BT-H FM1R or one of their K1F replicas. These mags use CDI technology and have electronic advance/retard built in as standard, so you could keep that plain drive pinion, it has the same taper as the magneto. Bad news is they're pricey, and they won't fit the Bullet crankcase flange without modification, though it has been done. My AVL hybrid runs one as will my Not a Fury. Count Johnny who posts here sometimes has one on his 612 custom. We like!



Speaking of CDI, Electrex World offer a crank-mounted CDI kit which is self-generating, and similar to the PVL systems are hosts sell, so effectively a modern flywheel magneto. There is an option with lighting coils from Electrex World, which you would want as it replaces the alternator. Good news, it's cheaper than a new BT-H, not so good news is the lighting output isn't an awful lot. You could still have the SR1 fitted for show, but with no pinion fitted.



Bullet Whisperer developed a hybrid ignition with a twin-plug head, a crank mounted CDI with normal ignition timing firing one plug and an SR1 mag running fixed ignition firing the other, but with the spark set in the fully retarded position. The PVL CDI ignition apparently wasn't the easiest of starters, so keeping the fixed advance SR1 gave a nice fat spark for starting, but once the motor was up and running, the PVL CDI advance curve kicked in and took over the ignition.



Otherwise, go old-school and fit a manual advance Lucas N1 magneto. You'd need to sort out a mounting platform with straps to hold it down, and a suitable oil seal for the magneto pinion. Again your Indian plain pinion would do fine.



A.

[vince]

Hi, I converted a matchless single ATD for my Enfield, machined centre out of an enfield distributor gear and took sprocket teeth off matchless and married them together with epoxy, its been running for 4years . Vince
PS this reply appeared in the wrong blog for some reason ,I thing my computer cant spell!