930 concentric

[Topdad]

Been trying to get my A10 back from her slumber but after having what I thought was a good clean up  she still isn't running .Mag as now been cleaned and pickups back and plugs sparking well .so carb ?? can you remove the idle jet ?  thanks for your time bob

[muskrat]

G'day Bob.
Some yes some no. The 930 Mk1 has a removable pilot jet screwed in to the body above the float. The Mk1.5 has a pressed in jet in the passage at the end of the air screw hole. It's only 0.016" and blocks easily.
Good luck.
Cheers The Premier 930 has a removable screw in pilot jet on the opposite side to the air screw.
Watch this video https://tinyurl.com/mtapz6ch which is the Mk1.5
I have found the easiest way is to put the carb through an ultrasonic cleaner. I have one myself but at the shop we charge $25 to do it.
Or remove the air screw and blast carb clean down that hole and the hole in the mouth of the carb followed by compressed air.

[Triton Thrasher]

If we disregard two-strokes, only very early Mk 1 Concentrics had a pilot jet screwed up into the body.

[Rex]

True, most are running with the actual brass jet removed leaving just the tapped hole.
Many years ago on a T120 I assumed my bike had been the victim of a forgetful bodger, so I bought and fitted two new brass jets.
It made absolutely no difference to the running or starting.

[JulianS]

Most mark 1 concentrics had a pressed in pilot jet, not a screw in one. You do not need both.

See this article on the Amal/Burlen website on rebuilding the concentric and see under "pilot circuit" for cleaning the pressed in jet.

https://amalcarb.co.uk/technical/rebuilding-mark-1-concentric-carburetter

[Topdad]

Thanks everyone for there input now have restored what I knew 4 yrs ago but which had gone completely from my memory cheers Bob