classic motorcycle forum

Nookys Nuts in the UK is another supplier who specialise in British threads. Nuts are correctly chamfered on one side only. Small bag of mixed BSC nuts is £12 plus postage.

Tread carefully here ?

I don't know about the G2 Bullets, but earlier Enfields had those nuts turned down a shade at one end,
so as to go into the CIRCULAR recess in the timing cover. This means hex nuts won't go.
But they may have changed this arrangement for the Bullets ?

Hitchcocks in the UK would have the real deal.
https://www.hitchcocksmotorcycles.com/partsbook-pages/1444

I think 30 and 31 are what is required (no quantities listed, so cannot be sure.)
They look like just plain cycle thread 1/4" nuts.

Luke at Britcycle.com.au had them NOS at $1 each, cad ? plated.
You'd have to chase the washers - stainless ?

Interesting sounding project. ?
Can we see it when done

Have taken on the resarrection of a 350 Royal Enfield and has been robbed of most of the engine case nuts. Has anybody got any suggestion as to where to get nuts from in Australia for a reasonable price? Thanks.

It hasn't appeared. I'll start again.
This engine never did well, I think mainly due to its dismal lubrication system. Introduced in 1923 it ha the same system as its 350 side valve stablemate. Namely a total loss system that merely pumped oil into the engine to just splash around and hopefully oil everything. In this engine, being of ohc operation the oil line entry was up on the cam gear so you got steady drips on to the valve gear before it theoretically dripped down the cam drive at the cylinder rear to the timing gear train and hopefully after that through in to the crankcase where the big end and piston got what was left. Given the pump was driven as usual practice from down on the timing gear you can imagine how long it took before any oil got up to the cam gear and then started its long drip down to the bottom end. Valve guide lubrication to the exposed valves may have happened on the way through but don't hold your breath. 
It wasn't a happy arrangement and Matchless fiddled around with it for years eventually fitting a duplex Pilgrim pump with the top and bottom ends each getting their own feed.
By this time the factory only fitted it as an alternative 'sporting' engine in their 500ccc ohv single Model V series bikes and this is the version sold by Shannons. The engine did not survive the across the range change to dry sump lubrication in 1930 but that year the new 400cc  Silver Arrow was the Matchless pride and joy. Who needed to be reminded of a dud 350 ohc effort.
I know the Shannons bike quite well. I knew both the original gatherer of all the parts and the next owner who finished it. They were good mates. Both gone now. It would be a very interesting bike to own but definitely one to trear cautiously.   

I like the head - viewed from above, the angle of the inlet and exhaust ports look to give a nice swirl.

The "sideways" nature of things does seem weird, particularly for a vertical single cylinder. But there was precedent in the sporting ohv Douglas twins, beginning with the Sports model in 1920, running through the Dirt Track and into the 1930s. Like the Matchless, all very sideways! Even earlier was the racing Matchless ohv V twins in the 1914 (?) TT, which used an unusual MAG (Motosacoche) twin with sideways heads. I wonder if the Matchless designers had one of these engines in mind when they began work on the LR in the early 1920s.

The missing bits - particularly all the top end of the valve gear - is certainly a problem, but it's the sort of thing that lurks in sheds as a curiosity, interesting but useless!

Leon