Dezza

Why not bring your DR along too ? It has some pretty cool modifications.

Weather permitting, I should be able to ride up to Donington at least one day on my Spondon so count me in too please

This statement holds for almost all bikes relevant to the OSS forum

Open up the faulty item for inspection. My efe starter spat its dummy out 20+ years ago. After removing a load of carbon dust it's been fine ever since.

Shifting a GSX1100 engine definitely requires a helper, unless you're someone in training for one of those 'world's strongest man' events.

Mag 2 didn't come out until 1982 so I'm guessing a 300s frame is likely a late Mag1, which aligns with the tank if it's the one supplied with the frame from new. Enfield will be able to confirm this if you email them.

When a frame was built and when a bike built around it was first registered aren't necessarily going to be close. My Mag 2 frame is number 8... and I have a doc from Harris stating it was made in February 1987. The bike was first registered May 1987 but the time made to 1 registered could be years. 201 would have been made by Harris years before 1987.

TMR 38, same spacing as oil-cooled GSXR https://www.Eblag.co.uk/itm/274976018014?_skw=mikuni+tmr&itmmeta=01KVDS57YK6HF4YX1QARDT92BF&hash=item4005d90e5e:g:5IsAAOSwibJfSQZ~&itmprp=enc%3AAQALAAAA0GfYFPkwiKCW4ZNSs2u11xAB47TU9I3r2aVzQmYCnOpltCTls7gJJvMipMY8vomxBT98Z5VykZphv1RS%2BzxGRwkEH1veNuJSAvVVEeV5AsazLhgn8vzZX2EPgTNbeDIxkd66BfOJwmgQ2isiyy9e%2FUudr26v6fpxbBQMagRqyQZTNuSPFzYFRbCQDAKhnplCP3U1BtXfTY2luOoJnuyMYvqlqFOK%2FkG2cMsj8c9MwuJfC6YrfLAgm53YQB9%2FD6YmLR6KO6cTX04K1DiaG9vXYLc%3D|tkp%3ABk9SR77_lLnbZw

If you contact what's left of Harris at Royal Enfield and provide a frame number then they'll tell you. The tank is Mag 1.

It could be corrosion/bad contact between the engine and frame. I had this problem with my Harris Magnum years ago and agree with @Blubber to run a seperate earth cable from the starter to the frame to eliminate this possibility.

Try Nick Pepper at SPS for inlet rubbers. The 1100m/n rubbers will probably accommodate BST38s if you end up retaining the cv carbs. The rubbers for the 750RR may also work for your application, which I think are still available from Japan.

BST38s may not fit as the 1200 engine is taller than a 750 and they're an effing enormous carb: much bigger externally than BST36 and especially the very compact BST34s. No need to put you off though. If the BST38s won't go in it will just be a good excuse to fit RS carbs or similar . If you have the slabby loom then it will work well along with an 1100 slabby CDI with a B12 engine but you need to change the pick-up and rotor too. The b12 CDI has completely different connector pins to the slabby unit and requires a resistor in the ignition switch. Fitting a slabby ignition to a B12 also perks up the low and mid-range because of the slight timing advance.

Yes, the parts and numbers needed are detailed in the manual supplied with a set of RS carbs. I did a cable choke conversion on my RS carbs. Details in build thread: Spondon GSXR1100. I got the carb bits from Allens who now don't exist and used a cable that I already had.

In my experience, banjo bolt switches vary considerably in quality, reliability and cost. Avoid ther cheapos. The decent ones e.g. Goodridge, now cost a lot. Some AP master cylinders have imperial threads, even ones made right up to the 1990s, which also complicates things a bit.

Trago Mills is still going? I remember being dragged into the place as a kid by my parents whilst on holiday in the mid-1970s