Petrol Tanks 1971 750 commando

Did the 1971 commandos have metal petrol tanks originaly.

No, they were fibreglass.

Metal tanks appeared for the 1973 850 (and 750) models,
and LAB always quotes they were mandated as compulsory in June of 1973
(I think is the date he quotes).
Nortons knew it was coming, and acted ahead.

Rohan said:

No, they were fibreglass.

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The exceptions being the Fastback LR and Interpol tanks.

Rohan said:

Metal tanks appeared for the 1973 850 (and 750) models,

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1972 750 tanks could also be steel from 203200 according to the RGM tech. notes, and 'Steel' as well as 'Glass Fibre' tanks appear in the '72 parts book.

Mine was fiberglass for sure. I replaced it last year.

I have two petrol taps on my 1971 750 tank',is one for the reserve and one for the main ,or do i require both.I am feeding a Miknui carb

If you are going balls out on full throttle, you'll probably need both taps on.
If it ever falters with only one tap on, you'll know that one isn't enough.
If you keep the reserve in reserve, you probably won't need to push it to the next fuel pump as often !!

Run the fuel out of a full tank (into a drum) and see how much is delivered by each tap, and at what rate.
See how much is left in reserve.

If its a say litre or even 2, you can calculate how far reserve will take you.
One litre is roughly good for 10 miles (if you get 45 mpg).
If you have a gentler throttle hand, it will be a bit further.

I would have though you would have known most of this,
from your learner days on a spagforth whippet. ??

I'm just replacing my taps. They have some rubber part inside that swells and decomposes and severely reduces flow, mine both need to be on if I want ride at all hard.
I suspect there are a lot out there with this problem.

It's well worth checking as the lean condition could be catastrophic for the engine at high speed and heavy load.