It does look like it has a pump. I have a small carb that says "AMAL" on one side & "Mikuni" on the other. I don't know what it was used on but it resembles '60s Mikunis but with a choke plate, which is missing. Cheers, Don.
The connection between Mikuni and Amal go back to 1932.
The relationship between fuel flow rate and numbers stamped on Mikuni main jets is very similar but not quite identical. Flow rate depends on the viscosity and density of the fuel, and I believe the reason for the small difference is that Mikuni, who almost certainly would have used AMAL fuel calibration boards in their factory, simply used different fuel. That's all it would have taken to account for the fact these somewhat arbitrary numbers are nearly the same, but different (nb. arbitrary in the sense that the choice of pressure head for the tests is arbitrary).
I've probably written this before but, if so, it was long enough ago that I've forgotten it. The '392' on the side of the Mikuni/AMAL carburetor in the first post of this thread isn't a model number. I have a period Japanese-language brochure on these carburetors and I asked a visitor who was working with me at the time to translate something in it. In doing so he also pointed out that the numbers '3', '9', '2' when pronounced separately sound like 'mi', 'koo', 'nee'.
However, Mikuni's play on words, er, numbers is even more complicated. It turns out in Japanese the numbers used depends on just what is being counted. That is, completely different words are used for counting, say, eggs than are used for counting people. In order to sound like 'mi-koo-knee' two of the numbers in '392' come from one way of counting and the third comes from another. Apparently, though, if you are fluent in Japanese you immediately recognize what the 392 signifies despite this complexity.
The early Japanese motorcycle industry relied heavily on copying British, German, and US designs, sometimes under license, sometimes not.
The same can be said for the early British motorcycle industry, that relied heavily on copying Continental designs. The French deDion-Bouton engine got several British (and U.S.) manufacturers into business, some under license and some not. The design of Lucas and BTH (and others) rotating armature magnetos was copied directly from Bosch. The British BA thread system is a direct copy, with a trivial modification, of the Swiss Thury system. And so on.
For a manufacturer in any industry (or country) to launch itself fully formed with a truly innovative product is the exception rather than the rule. Much more common has been to start out copying something under license (or not), possibly with incremental improvements, and only after cash starts flowing to slowly evolve away from the original product.
O/T but interesting I think ; At the beginning of WW2 the Japanese had several air cooled radial aircraft engines of 1000-1800 HP . These were originally license built USA Pratt & Whitney and Wright designs reworked by the Japanese to suit their needs. As the war progressed they needed engines in the 2000-2500 HP class to keep pace with new designs from the USA. The Japanese,because of lack of materials and or engineering were never able to manufacture reliable high power engines.
650 Triumph modified production LSR record holder 133.1 MPH... Twin 650 engine Triumph LSR that goes sorta fast...
That's interesting. The Japanese number 3 is - San
Spelling may be wrong. Ich 1 Ni- 2 San 3 She 4 Go 5 Ruckho 6 Can't remember 8 Ku 9 Ju 10
Nice story though
Actually, you're only partially correct. All Japanese characters have two readings, Chinese (on reading) and Japanese (kun reading). Your translations of the numbers are the kun readings. In on readings 392 translates as mi-ku-ni.
Nice try though.
When people who should have known better cautioned me about the dangers of motorcycle racing, I always told them that a fear of death is nothing more than a fear of life in disguise.
Thanks for the offer. I have your head all cleaned up and just waiting on the correct pressure valve springs to show up and its going on the bike. I will let you know how it works out and then on to working on getting mine setup.
1955 BSA Bantam D1 Plunger 1956 BSA A10RR Street and LSR Bike 1961 BSA C15S 1966 BSA spitfire 1969 Triumph T100C 1970 Triumph TR6R 1972 BSA Lightning LSR Bike 1974 Triumph T150V