Oversize the thread and make a suitable replacement adjuster. 26 TPI British Cycle thread. Doing it that way will give the strongest result . Being on the chain side you don't want it to fail. Nev

They are not that radical anyhow. Nev

The original 30-on has has a rather flimsy item there. I'd try to adapt the later one.Nev

John, clean out ALL the idle system holes carefully and check the float height and it think she will run sweetly. Looks like your jet block is a good fit. Brass (and Diamonds)are forever.. Nev

It's definitely a Lucas pick up from the Late 20's period. Usually at least one of the projecting prongs that locate the CORK gasket in place are broken off Around that period the Magneto's are only held on by 2 hard to reach bolts on Ariel (Same as if a TT BTH is fitted to later "competition' ...

Having another look at what you have It appears as if the CAMSHAFT teeth may be a more modern profile and not matching the other. It's NOT meshing deep enough, also.. I don't think ARIEL ever changed after going to the finer teeth in the early 30's but many gear cutters don't carry the earlier tooli...

I couldn't access that . I just tried twice. It will be my computer.. It's not likely to fail but if you WANT it right get it right as it will Probably worry you.. Measure the pinion teeth depth with suitable small rollers IN the teeth, opposite each other allowing you to use a micrometer and COMPAR...

Those Irving Vincent motors make the Most impressive noises at Broadford I've ever heard any bike make. Getting back to the metal used in the finished product you can see some alloys look whiter and ringing sound through the fins more This is generally an indication of the hardness. Some head metals...

Vids with sound always seem to magnify whirring and tapping noises in Machinery. Nev

LEE have you got the raised handlebars with the Crossbrace fitted? Nev