Single Amal Conversion

What is a good baseline for setting up a single Amal monobloc on my ‘66 N15? Pilot, main, jet, and needle position? Also, would I need to change the cutaway?

Thanks in advace.

These are the factory specifications for the single Monobloc 376/294 on the early Atlas: choke 1.16"; floatchamber needle seating raised by 1/32" washer; shortened tickler fitted; main jet 400; needle jet 106; pilot jet 20; throttle valve (slide) 3 1/2; needle taper C; and needle position 4. I run this set up on an early Atlas and it is satisfactory although the pilot jet might be a bit rich. The early Atlas probably had lower compression than your motor. I don't think the choke is terribly important - I never use it. Otherwise these specs seem like a good starting point.

My single carb Atlas had a split sleeve reducing the inlet dia in each inlet port, for slower running, could get 12-15 mph in top gear!
( pilot jet was 15)

Bernhard said:

My single carb Atlas had a split sleeve reducing the inlet dia in each inlet port, for slower running, could get 12-15 mph in top gear!
( pilot jet was 15)

Click to expand...

Seems to me, and I may be wrong, but raising the float chamber needle with the spacer (washer) raises the fuel level in the float chamber above the standard level marked by the dot moulded into the float chamber cover. Presumably this was the result of some experimentation by the factory and was intended to compensate for the use of a smaller main jet than that used on the twin carb bikes.

Bodger said:

Seems to me, and I may be wrong, but raising the float chamber needle with the spacer (washer) raises the fuel level in the float chamber above the standard level marked by the dot moulded into the float chamber cover. Presumably this was the result of some experimentation by the factory and was intended to compensate for the use of a smaller main jet than that used on the twin carb bikes.

Click to expand...

Actually, to revise my original speculation about the float needle spacer, by memory, the twin amal set up with the single carb with the float chamber and the other chopped, also spec'd the spacer.

I should have mentioned I have an Amal 389/236. Do they setup the same as the 376?

If you go here, you can find the specifications for all monobloks, and the bikes they were used on.

http://porklips.org/~mason/moto/amal_specs.html

If you study the charts, you will find the Amal 376/294 was used on single carb Atlas's, which I think would be appropriate for a single carb N15. Bodger, in reply #2 above has given you the setup for the 376/294.

Slick

To install a single carb on my Commando MK3, with the splitted inlet manifold, what diametersize of the carb air outlet do I need?
I tried with Amal size 32 mm and main jet 280, but respons on throttle to slow and exhaust explosions during engine braking.