Mark 3 Jets

Can anyone advise what is the standard jet for the Amals in a 1975 850 Mark 3?
Thanks,
Stephen

My 75 MKIII is happy with 260's. I have an open 2 into 1 megaphone and K&N filter and because of that it was running really lean 230's.

Captain B said:

My 75 MKIII is happy with 260's. I have an open 2 into 1 megaphone and K&N filter and because of that it was running really lean 230's.

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My Mk III with a Web Cams 12a and a 9.7:1 CR is very happy with 220 mains. I started with 260s, when to 250s, went to 240s, went to 230s and ended up with 220s, I was quite surprised.

I find myself shying away from RPMs above 6500, but if I wanted to hold 7000 RPM I would install 230s, maybe 240s, but I have never had a lean surge with my 220s even after abruptly coming off a full throttle attack to an occasional blast to 6500+.

My sense is that a Commando has to be in a very high state of tune to drink from a 260 main jet (at WOT) and not just be hosing down the cylinder.

I'd like to see what other members are using for main jets; keep in mind that if you don't use 3/4 to WOT a lot you really don even need a main jet. Literally you could leave the main jet out and not even know it if you use part throttle openings.

RS