Yesterday went out on my 49 M33 on stopping at traffic lights the box would not change and the clutch lever developed a large amount of slack. Had to lift back of bike to move it. After a lot of rocking the clutch lever came back to normal, thinking it was a broken spring I started the bike in gear on the stand then rode home in second. I took off the ouuter cover and apart from all the bits looking loose and wobbly all looked ok no broken springs, on after fiddling with the gear change to see how it worked" it's all different to my swinging arm gearboxes" I put the cover back on and every thing now works. Why did the clutch lever develope so much play and what happened to the gearbox change.

Hi Ian..A lack of oil in the clutch casing combined with 'hanging' on the clutch will cause the clutch to overheat..The plates then expand, which makes the clutch 'drag' due to lack of clearance (making gear selection difficult) but also makes the total hieght of the 'stack' of plates higher..that effectively makes the pushrod too short so you have slack in the cable...When it all cools down again clearances and operation return to normal. It is best therefore to select neutral as you pull up rather than holding the clutch in whilst still in gear.
Another possible, but less likely cause, is the pushrod being a little tight (through lack of lubrication and corrosion) in the mainshaft bore..that can cause the clutch to stay 'lifted' when you release the clutch lever, giving a lot of slack at the lever..when it reurns to its normal position under spring pressure everything works again. I have had this second problem but it is not that common in my experience...Ian

email (option): ian@wright52.plus.com

Plenty of oil in the chain case the problem was the other way round, stopped at lights and thought I was in nutral bike stalled found I was stuck in gear and couldn't get out tried rocking the bike then found I had lost the clutch couldn't disengage then it came back and was able to move the bike with the clutch disengaged, I rode the bike home in second gear 5 miles stopping at traffic lights with the clutch in with no ill effects, found nothing amiss when I took off the outer cover played with the bit inside put the cover back on every thing works.strange.