Unleaded fuel on a Model 7 Norton

... be fine. Cast iron heads without valve seats of different material are the most vulnerable but the test that the FBHVC did a few years back with BMC A series only showed problems when held at high reves for extended periods of time.

My 1952 ES2 (cast iron head) runs perfectly on modern fuel.

As Ian says, unleaded fuels are fine in our cast iron heads without inserts. My 1951 ES-2 runs perfectly on our 91 octane unleaded petrol.

A few years ago I took a n.o.s. Big 4 barrel to my engine reborer and asked to get suitable valve seats fitted for unleaded petrol. His comment was not to waste money as I would not do enough miles to see any valve recession

When your Dommie left the factory, the only fuel allowed to sold was lead free and had octane rating of 72. This 'pool' petrol was just about usable. With the end of rationing in 1953, branded petrol was allowed and fuels of higher octane rating boosted, mainly by the use of tetra Ethyl Lead,.appeared on the forecourts.

Modern high octane lead free fuel should be no trouble, 

If you live in England, Wales or Northern Ireland, I would recommend Esso Synergy Supreme+ with the red label.  This fuel is currently Ethanol free but not available in Devon and Cornwall and a very wide Teesside ethanol zone.

This is the fuel of my choice and causes NO damage to the fuel system.

Use it or lose it.  E10 coming in the Autumn, its the agenda..........

Not available in Scotland either.

Hi John,

Correct, why I left North of the border out of where to buy E0.

When push comes to shove there might be the option of AVGAS (With antifreeze)  OR Anglo American 4* Leaded racing fuel. (Where I might have to go if forced into it)

But at the moment I'm perfectly happy with my Esso E0 with a tot of RedX lead replacement in my singles.  Enjoy the Sunshine............