52 A7 Gearbox

[starfield]

The change on my 52 A7 gearbox is clunky particularly 2-3 and 3-2, though 4-3 and 2-1 are not silky either. Is this common on these boxes or does it suggest attention is needed? Various techniques to improve my gearchanging skills have not altered the clunkiness so far. I don't think its clutch adjustment as finding neutral is always a doddle and it slips into 1st at startup with  never a murmur.

Bike goes lovely otherwise and I don't want to waste summer riding time for no good reason. On the other hand I don't want to damage the box by using it further if a problem is indicated.

Any suggestion as to cause and cure would be appreciated.

thanks

Peter

[iansoady]

I find the gearbox on my 1961 Flash very clunky compared to the Norton Commando I had for 20 years. It's even notchier than the Velo. I've decided it's just the way it is. Contemporary road tests always suggested that a measured approach worked best and that's certainly true of mine.

[starfield]

That's interesting because my comparator is a 1961 G3 Matchless with AMC box - silky change across all gears. The BSA box is I fancy marginally worse than my 1970 BMW R75 (4 speed box) which has a poor reputation for change action.

Peter

[muskrat]

G'day Peter,
                 the box in my '51 (same as yours) is fairly clunky. Slow positive changes works for me. Check the detent plunger is ok and adjusted with about 2 or 3 threads showing when locked up. Primary chain not too tight and clutch not draging.
 I add a little teflon additive (nulon) to the oil.
Cheers.