Dear all, I have trawled the messages for info on single carb jetting on a 930 concentric. Could folks in the know please confirm these settings may be OK?
280 Main Jet, 106 Needle Jet, No.3 Throttle Valve, 25 Pilot Jet, Needle in middle position.
I intend to order a new Premier 930 from Burlen soon.
Thanks in advance. Jack
Thankyou Phil. So the only…
Thankyou Phil. So the only variation to jetting on your Atlas was the 270 main jet? I am close to needing the carb. I was going to use a bellmouth with gauze to stop small birds, stones etc. entering. I take it the K&N mesh is none too restrictive too?
Every bike varies. The set…
Every bike varies. The settings are only a guideline. Valve wear, minor manifold leaks and air filters will all affect the running.
I used a K&N type of filter because it does a good job of keeping out most of the road and air debris but does not greatly affect the jet sizes. On my Atlas, at the yearly service, I used to clean and then dunk the filter in old oil to wet it. This then helps to filter out some of the finner dust.
Another point worth a mention. The Premier carbs are supposed to be much better made than the old Amals of the 60s & 70s. In this respect they allegedly have finer build tolerances and hence run more efficiently. Implying that a slightly smaller main jet, than originally recommended, can be used.
Cheers Phil. I think I mig…
Cheers Phil. I think I might order it up today then. 270 main jet.
I've fittedtwo1974 Mk2a's with a single Premier & two pairs on RE Interceptors. All worked perfectly with no juggling of jets, just a tweak of the air screws. I like them a lot.
Your settings are what I used on my Commando but the carb was a 932 Premier. On my 1965 Atlas I tried both a 930 and 932. The 930 was much easier to tune for idling and low revs. I used a 270 main jet plus a K&N type of mesh filter. Usual story of trial and error, frequently checking the plug colour. This combination always gave easy starting plus 60 mpg when fast cruising.