The original carb on my '49 M21 engine has become so unreliably leaky that it's becoming a danger.
When the needle doesn't seal or it leaks elsewhere the fuel drips come rather close to the hot exhaust.
I think I should switch to a monobloc for peace of mind.
Can anyone provide the right spec please and also - if anyone has one for sale - please let me know.
Thanks,
Bernie
Hi Bernie.
Taken from the Amal catalogue.
M21 Home and Export settings, for 1955-1960
Carb number 376/88 1957-1960 (or 376/23 - 1955-1956 - settings are all the same, so don't know what changed)
Bore 1 1/16
Main Jet: 250
Pilot Jet: 30
Needle Jet: 106
needle position: 2
Throttle Valve: 376/0605 (#5 cutaway for 376 carb)
Interestingly, the AA order model bikes, stuck with a 276 right till the end of production - god only knows why!!
Great - many thanks Allan!
Phone Burlen, Hitchcocks or Surrey Cycles, tell them what it's for, pay them some money and they do the rest.
I'd go for an Amal premier personally.
Confirming the specs from Allen G. Your air screw at 1 and a half turns out. I got a brand new 276 and it leaked like a colander so got the 376 which worked immediately with hardly any tuning needed.