harrym, (welcome back, we 90+s were getting a bit worried - send not to to ask for whom the bell tolls - it tolls for thee, etc !) and
DHfan,
Quite a few hares running here.
harrym, your tale of the old despatch rider's 350 Royal Enfield brought back memories. It was the only motorbike I ever tried (in India) during the war. It had the quadrant gearshift on the RH side of the tank, and I didn't fall off, and that's about as far as I can remember. Never had a m/bike before or after that (if you count out the BSA "Winged Wheel", which hardly qualifies, I suppose).
As for methanol, you can produce it cheaply and abundantly from vegetation (sugar cane in Brazil, I think, is fermented and distilled to produce the methanol on which all their cars are modified to run); it is the feedstock of choice. Didn't ICI at Billingham find a microscopic lichen which loved the stuff, and could be harvested by the ton into a greenstuff packed with protein and said to be suitable for human consumption. Never heard what became of it after that (but I sometimes wonder when looking at the exotica along the supermarket shelves).
In your case, why not keep the methanol in the tank when going to RAFVR training? Does it smell different, or is it detectable in some other way? Was it available in any quantity "off ration", in '47, if so where from, and what did it cost in comparison with the evil, rationed "Pool" stuff? (We're not talking about methylated spirit here, are we ?), for that was certainly available but very expensive (compared with the 9d/gallon domestic paraffin which you could get at any garage or ironmongers) and which was the dilutant of choice to eke out your "Pool" ration.
Even your ingenious gravity-fed dual-fuel arrangement was not without copiers. Somewhere in the tale of my Valley days ('50-'51), we had a chap on 20 Sqn with a big old Bentley "Green Label" open tourer. Clearly there was no good putting his meagre monthly ration (2½ galls?) into the cavernous tank, where it would simply vanish into the rust, sludge and water on the bottom. So he decanted it into old lemonade bottles, and like you, stuck them up in the folded hood at the back, and gravity fed the three huge carbs by a system of rubber and plastic tubing. It worked fine, and he always kept a couple of full lemonade bottles under the back seat.
And we all benefited, for the whole bachelor element of us could be crammed into the huge boat-like body for a sortie to the "Tatty" club in Rhosneigr, or for what passed for a pub in those parts. Naturally, we all contributed, from time to time, a bottleful to our benefactor, for fair's fair, after all
Even the "Amals" are mutual friends, although mine were tiny (W/Wheel) or small (Isetta), and all I ever did was pull the top off to free a stuck needle-carrier block (having learnt, early on, that it was no use messing about with the needle setting - leave it where the maker has put it!) And you had to be careful not to bend the needle.
DHfan, tin globules functioning as a catalyst was a bit far-fetched, I suppose, but when unleaded petrol came in, the old banger I was running (can't remember which one) did all right on one of the proprietary additives. What was happening to the valve seats, I knew not, neither did I much care, for the whole thing rotted out before that became a problem.
I was told that the unleaded petrol idea originated in the US, the theory being that lead particles in the air were degrading the intelligence of the little ones, their noses being closer to the ground and so to the exhaust pipes than adults. After a generation of lead-free petrol (less efficient and therefore worse for the environment), they looked for the promised improvement in IQs - and found none. The little dears were just as thick as before - but we were stuck with unleaded petrol for evermore.
Happy days ! Danny.