I'm on the home straight with my SQ4 gearbox now. In what may be the second to last trial assembly, I have 1.11 movement on the sleeve gear, gearbox in top, sprocket not tightened up. I'm now ready to make the spacer to move the sleeve gear inboard. I've currently got 2/3 of the sleeve gear spline l...

The fun bit is getting the temper right - I had two goes at that with the stand springs. The side stand clip might be easier (as it's a bit smaller) but I found controlling the temperature across the whole spring simultaneously quite difficult. I've used a domestic oven for things like knife blades ...

I'd attempt to make one. Alan Moore did some very good posts on making W/NG fields stand springs which would show you what to do.

Wow. Well done guys, it's so impressive what a group of dedicated people can achieve.

2 questions: Has the nut on the kickstart end of the mainshaft got a large internal chamfer on the side which should abut the kickstart ratchet? No. There's a small chamfer, sufficient to clear the bottom of the thread on the shaft. I'll turn a shallow depression there, 0.5 mm deep, to reduce the e...

Here's the mainshaft end float Mick, you can see the gap under the nut.


Light bulb moment - the mainshaft doesn't pull up against the bearing, because the end float is needed to allow mainshaft third to spin.

Not sure how to rationalise near zero axial on the mainshaft small bearing and 0.040" end float on the shaft, was the clamping to the bearing inner removed when measured? No - I hadn't dismantled anything bar the clutch at that point. I'll put the mainshaft back in without the rest of the clus...

There's probably 0.5 mm of longitudinal movement in each of the selectors. Some of it comes from here: IMG_20240124_120850.jpg There's no perceptible movement in either of the ball bearings. They've only done 5000 miles. Fifteen minutes work with various micrometers revealed this: Layshaft 2nd bush ...

Not yet Mick - basically I only had time to pull it out and get it clean. The forks look good and they are a good fit in their grooves; they move easily on the drum but I haven't had the pins out yet.

The latest news is that the BA gearbox from my Square Four is now stripped and washed out. If you recall, some dogs were clattering at idle, in neutral. For the record, there's 0.88 mm (35 thou or just over 1/32") end float on the main shaft and about 0.23 mm (9 thou) on the layshaft and select...