classic motorcycle forum

But if you take a critical look at things, the English (British) seem to have a penchant for taking
others perfectly good thread systems, and 'developing' it into something they can label as their own. !
So we have BA, which is a adaption/mangling of a Swiss clockmakers metric thread, 47.5 degrees and all,
such that present day metric nuts are a (poor loose) fit.
An indication of how closely they copied it. ?  But not copied it exactly ...

Took/adapted/developed/whatever....you seem to have some deeper narrative you want to post about.
Do the Wokies know about this alleged thread appropriation? I don't want some pink-haired harpies picking up on your posts and cancelling my BA thread selections.

Well, then you have to ask WHY all the (very) British thread standards emerged, when all the early motoring was done with French engines

The thread and fastener standardisation started by that nice Mr Whitworth started lonnng before the era of of early French IC engines...

Smiths meanwhile swallowed their English (British ?) pride, and used all metric
on the chronometric speedos, for many a year.
But reverted to BA etc on the magnetic Smiths range.
Odd, given that they had all that metric machining capability ?
Nationalism is a strange disease ...

Given that the chrono was based on a French Jaeger design keeping the Metric dimensions and specs was likely down to laziness, but that said the French components used "French metric" threads which required conversion to ISO metric stuff in later years.
Seems like even the so-called "universal" metric standards were far from universal even as late as the 1960s.
Given the meltdown of the old industries in the mid 1960s, who can tell the reasons why the reversion to BA threads on the later crap mag speedos, but whatever the reason(s) claiming that some sort of nationalism was the root cause really is nothing short of bizarre....

Treat yourself (if you haven't already got one) to a tailstock die holder if you need to cut a BA thread on a lathe. Life really is too short to screwcut a BA thread on a lathe though..

It may wind on, but I'd never describe it as any sort of "fit".
Rather like OBA and M6, slack as something very slack, although there have been claims of interchangeability by some...

Wouldn't it be possible to fabricate what you need with some basic metalwork and welding?
Not going to pass any originality tests but would allow the resto to progress while searching further for the real ones?

Some civvy '66's have a Yale type ignition switch set below a rotary light switch in the side panel, but the military build 3TAs have no side panel covering the battery and and side-mounted air filter. I guess it depended on the military spec required.

Is it not possible to use the tried, tested and traditional pencil down the plug 'ole with the timing locked on full advance? Maybe set at  5/16 BTDC and see if it runs?