Laydown Gearbox

Try getting hold of a later Pitman's  'Book of the Norton' or Garratt Maintenance Manual.

There are also a couple of useful articles in previous Roadholders written by Bob Proudman and Barry Stickland. Just dial into the Roadholder Index above.

Norton Gearbox Servicing by Mick Hemmings DVD

... but the internals are almost identical - as they are with the earlier upright & doll's head versions. All that really changes is the positive stop mechanisms and even they are very similar. And the laydown and earlier boxes have the bronze thrust washer on the sleeve gear.

These gearboxes are quite straightforward units to rebuild.

1st gear small (main shaft) pinion from AMC box needs its extended boss on one end to be shortened.  Lay shaft (large with starter ratchet inside) is the same.

2nd and 3rd had 4 dogs until AMC arrived with 4.  Perhaps they can be swapped as a group?

Sleeve gears are different.  A full essay might be useful.

The AMC box had bushes on its output sleeve gear.  The  Laydown has a set or rollers.

Both of these boxes have different lengths of mainshaft depending on whether the box fitted to a single or twin or Commando.

The internal ratios also varied depending on the model and year of Norton. Later Commando gears should not generally be mixed with earlier versions despite looking similar.

Here are pictures of AMC and Doll's Head gears.  Second and third from Doll's Head appear not to have been turned over.  I believe Doll's Head and Laydown are the same.  Please correct me if I'm wrong.

Sept 2011 Roadholder has an article by Barry Stickland on the changes.

Hemmimg’s video also covers the Laydown box as I recall, but not in as much detail

dan 

I've watched the Hemmings DVD several times and it covers the laydown box in sufficient detail to enable a strip down and reassembly to be undertaken, plus a few hints on what to watch out for.

George