Scooterotica

Hi all I'm just doing my first full rebuild on my PX.

I'm building the engine and am stuck at the gearbox.

So my first question is:

1/ Will a late type gearbox fit the early type casings? (mine has the external oil seal)

When I fit the gears on the layshaft there seems to be a load of slack and the gears move about 6-7mm.
2/ I know there should be a top shim but should there be a bottom shim?

3/ Is there a way to I.D the gearbox so I know it is the correct one to go on my type of layshaft?

4/ how do you know if you have the gears o the correct way round?

Any advice would be very welcome as I have ground to a hault with the build at the mo.

Cheers
Russ ;o)

1 on very early casings you will have to change the christmas tree shaft but it depends on how early yours are

2 there should be nowhere near that play on late layshafts there should be a shim at either end but there only 1-1.5 mm thick

3 there is a way to id a gearbox but i dont have the measurements with me there in the workshop

if youre anywhere near sw london you can pop over and ill have a look for you

dont mix and match early, and EFL gearbox bits. including layshaft, selector box, cruciform, selector rod, everything. clutches are ok, but gear bits need to be kept in one set.