Correct gearbox 88

Hi Thomas, my 1955 88 is fitted with the "laydown" gearbox, as fitted from new. I suppose that all gearboxes have their devotees, making sure everything inside is in good working order, also the clutch operation is as it should be. My 650ss (1963) has the amc  box and works well.

In 1956 the Norton factory began to build it bikes with their own version of the AMC gearbox.

The change-over did not go smoothly due to the supply rate failing to meet demand. Consequently, there is a fair amount of confusion regarding which gearbox a particular bike should have for the 1956 year.

Also, although the production numbers are clear as to what took place at Bracebridge, there is no guarantee a particular  recently purchased Norton model has not had a gearbox change in its lifetime.

 The change-over to the AMC gearbox began in April 1956 but only for some bikes as the batches supplied were insufficient to match weekly production rates.  The very first batch being only 67 in total. Roughly just a third of a normal weeks production.

These gearboxes were allocated to bikes with engine/frame numbers 68761 to 68828. From then on old stocks of the ‘lay-down’ box were fitted to the next 101 bikes.

So from bike 68829 the ‘lay-down’ boxes fitted as standard, once again.

Supplies then arrived more regularly and so from bike 68931 onwards all the Factory production had AMC boxes fitted as standard. The exception being the International and Manx models which kept the earlier set-up until 1959.

So a -59 Manx should have a AMC box?

Roy Bacon states in the Norton Singles book that the change was in -58.

Phil...did the engine plates change? So is it easy to swap?

Also, what is the benefit of AMC box, if any? It's clutch release would have been cheaper to make (and heavier to operate) and perhaps it was more convenient not to put friction pads inside the basket, but there was no owner benefit, was there? Maybe the AMC box shape was easier to fit in different frames? Maybe the Manx kept the laydown to the end because it was better?

The changes only applied to standard 88 / 99 and singles road bikes.  The race based machines seem to follow their own rules. My guess here being the clutch operating mechanism and output gear support bearing made the Laydown better suited for heavy duty work.  I believe the engine/gearbox plates differ between the single downtube and Featherbed frames.

...so sang the Strawbs in 1972!

It was definitely the "Lay Down" box in 1955  I had a 1955 88 and still have some bits of it - e.g. most of the engine.

To paraphrase Scarlett - "1956 is another year."