I replied to this post yesterday but for some reason my reply has apparently been lost. However, others have covered the point which I made. Turning to Pete Silson's post, the pin is not necessary to connect the lower yoke to the steering column. All 1957, possibly 1956, and later NH models were not...

Its a 1954 model NH of 350cc. What year the rider is, I can't be sure.

The lever box contains only one ball ended lever, but it is 7/8" pivot to nipple centre. In an ideal world, you would use it on the brake side, but if you can put up with the pivot nut upwards, rather than the screw head, it is yours. Ideally, it needs re-chroming but if you want it I can send ...

Was it a Stoke-on-Trent registration by any chance?

The person putting the numbers in the log book had a bad day. The 7 at the beginning of the numbers should be a T. Whether the next character should be a 5 or an 8 is open to question - but the engine and frame numbers should be the same for a 2 - stroke.

Clean out the guides as best you can using a small bottle brush or similar with petrol or thinners. Clean the valve stems with petrol or thinners using an old toothbrush or similar. Lubricate and assemble. Run the bike, very gently. The worst that can happen is that the valve seizes in the guide, in...

I would advise WM3 x 18 as well.

Chris is absolutely correct. On the magdyno Square Fours 1936-48 the distributor base is cast as part of the magdyno end plate and so is completely unable to rotate. The position of the rotor arm can be adjusted instead. On the Mk I and Mk II models 1949-59 you can rotate the distributor base to alm...

Squares were usually fitted with a WM3 x 18 rim. Singles and twins usually had the WM2 x 19 rim. The rolling radius is much the same for either option.

To understand the X suffix to engine number DJ2050X you need to refer to the Service Bulletins, in this case number 85 of September 1949. The relevant section reads: " ALL SINGLE CYLINDER MODELS. PISTON AND OIL PUMPS. MODIFICATION. All 1949 models incorporating the letter 'X' after the engine s...