What Petrol

There are three options open to you it would seem.
You can just run it on modern unleaded and see if the tappets need adjusting too frequently - if they close up, then a lead additive should be used (option two). Some engines seem never to need any additive for some reason, whilst others do!! If your annual mileage is minimal, then the extra cost of additive may or may not be worthwhile - a bit of a 'suck it and see' scenario from all accounts.
The third option is to send the cylinder head away to have hardened valve seats inserted - more expensive but probably worth it if you intend keeping/running the bike for a few years.
No 100% right or wrong answers really, just what suits you and the bike best, dependent on useage I suppose. I've never seen a definitive answer on this question - but someone else on here may have!!

 

No I think that pretty much covers it :upyeah:

 

As stated above, there is no right answer. There are things to consider though. I run my 69 BSA A50 on normal unleaded but do less than 200 miles a year on it and the valves need no more adjustment than in the 'good old days' of 4 star petrol. Some bikes will not be the same even at low annual miles. Some people use additives and swear by them, others just swear at the additives. The additive question is a very 'sticky' one. Some additives can react with fuel if left in the tank for more than a few weeks, this can then produce a sticky goo that bungs up the carb. Amal carbs don't suffer as badly as Dellorto but it is worth checking with other owners of the same model if they have found an additive that works well for them.

I ran all of my 350 and 500 Moto Morinis on normal unleaded with no problem at all doing about 5000 miles a year, for what it's worth.

 

Hi Bullrush, I've a 58 thunderbird, look in thruxton pics, which I put a splash of redex in whenever I remembered, but I think it comes down to how many miles your going to do. If your thinking of doing a valve seat replacement you might as well run it on an additive until it needs it, if it ever does! Mine isn't running at the mo but its nothing to do with fuel, more electrics I think plus I'm finding it hard to get of my backside and do anything with it. Great bike put a photo up

 

If i'm right in thinking yours will be an iron head so as long as you don't run down motorways at 70mph all day all should be well. Just as a precaution i drop a piece of clean old lead piping in the tanks of my old Triumphs, pop it in a mesh nylon bag to stop it rattling about. Alledgedly it reacts with unleaded fuel and makes it safer to use in older engines.