carb output at low revs

My AJS M8 is spitting back through carb at low revs to the point it stops,looks to be rich ,I thought spitting back indicated it's lean,I have changed plugs no difference ,could my timing need adjusting?

Spitting back though carb, is it cold, need more choke , float level low, mixture /pilot screw need adjustment. Raise the needle.
Make sure your ignition is set correctly as well. I also had a weak valve spring on my intake valve (B33) which caused reversion through my carb at 1/2 throttle. Cheers

Often due to worn slide/body allowing extra air to bypass the cutaway also reducing the pull on the needle jet . More air /less fuel a double whammy!.

Has it ever run properly with you?

If you can get it to idle, spray the carburettor to head joints with WD40 while it’s idling. If there are air leaks, the engine note will change.

You can have a weak idle and still be rich at bigger throttle openings.