Yes, it's just the mounting brackets that make an assembly left-hand or right-hand.

I think it's to keep the spacer roughly in place while you press the second bearing into position & help keep it inline with the two bearings. The collar can't be an exact size because it remains stationary while the wheel spins so would wear a groove on the inside of the wheel hub.

Which Triumph forum have you asked, is it www.triumphtorque.com ?
If not, I'd try this forum, there's some very knowledgeable members on there.
I can't help, my Triumph sounds like the same set-up as yours !

They'll be easy to identify, they will be the ones that have rotted

Has the HORN/PASS button been modified by having the extended section on the PASS side removed ?
If it has then your L/H switch assembly is identical to that fitted to the 1976 Z900-A4. The colours of the lettering, yellow & white is correct, certainly for that year too.

I must be getting very old, what on earth are you asking ?!!!

Idiot light should only come "ON" when either front or rear brake is operated. Idiot light flashes if the brake light filament blows.
Operating the light switch should have no affect on the operation of the Brake Fail circuit.

Gavin, I not home for a couple of weeks so if you have no joy in the meantime I can photograph my bike & send you the pictures upon my return.

I used Dinitrol, but it was a number of years ago & not sure if it's still around. Ardrox, if you can get it is good stuff or Finigan's Waxoil.

steve bowdler wrote:The distance between the screw holes for the tank badges , are there just the two different sizes 120mm and 140mm

Ahhhhh ! My Z900-A4 is 140mm, (original tank).

Sorry, don't understand the question !!

Nigel, if you PM me your email address I can photograph my tool kit, which is original & send you said picture/pictures. The tool bag around one of the press-studs is a bit ripped, but that's all that's wrong with it !! I've never been able to post pictures on here as I'm not clever enough :oops...

Check out Harley crankcase breathers on Ebay, some of them are quite small & neat.

From memory there's three ball bearings in one of the gearbox shafts so that shaft has to be spinning to select anything other than first gear. Made the same mistake myself, many years ago !!

Not sure where you live in the country, but this guy would be well worth visiting or at least speaking to,

http://www.otcdynocentre.co.uk

Pete Alton is a very good guy & knows his stuff by all accounts.