Hi Gordon,

Hopefully it will be transformed with a leaner mix, although you might need to be a bit more attentive to the air lever. Keep in mind that because the jet is submerged on an early AMAC it only meters the fuel rather than spraying it - it doesn't have to be perfectly formed. You could just reduce the size of your current jet, either by running a  strand of wire running through it (if it really is a number 35, you'd need a strand around 0.020" diameter!), or filling the hole with soft solder and drilling it out with a jet drill. This is quite easy if you hold the drill in a pin vice and turn it by hand.

Have fun.

Leon

looking For the wee bevel gear that drives the dynamo from the mag drive , see photo .
Thanks 
Peter .

Many thanks Leon!
Our 2 3/4 had been running for years on the 35 main jet until its recent engine rebuild. However, there are concerns that a massively over-sized man jet could be causing oil dilution in the bores. Not a major problem with cast iron pistons but a concern with these new-fangled alloy ones.
A new main jet has been ordered.

Gordon.

Could some one take a photo of the BTH ammeter ,and one with a ruler on it so I can get the size of the face plate ( maybe 1.98") as I plan on getting some face plates
Silkscreened .
Also a few clear photos of the BTH with Powell & Hanmer  headlight
Brass plaque  as I think I have found a person to make them .
Thanks for your help.
Peter Allen

RADCO is close to god: he's almost always right. AMAC suggests 27 for an early 2 3/4 hp twin, which equates to 0.029". 

A 35 jet is 0.037" - enormous.

If you don't have jet drills, you can measure the jet diameter (ignore all numbers these days) with a darning needle. Slide it into the jet, mark where is stops, and measure the needle diameter at the mark with a micrometer.

Cheers

Leon

Gentlemen, 
thank you for your help. I hope my product is similar to the original.

Tomasz

My 1913 2 3/4 AMAC carb has a 35 main jet. According to RADCO's book this is too big - it should be a 26 or thereabouts. 
What should it be?

hi folks.
I have just joined and have 1920/21 project for sale.
Originally it was a project to be a joint venture with my Pa, long since departed.
At present I have not mastered the art of posting pictures,so if any one would like pictures they can be e mailed on request.
It would be a great project for an enthusiast.
On the next post I ll have a bash at loading pictures ,thanks for being patient.
Cheerz.
Phil.

Tomasz,

While I do not have one of these in hand to measure exactly, I have examined one.

The diameter of the collar is the same as the tube it sits upon. It is smooth on the outside (no knurl). It has a spigot that fits down into the inner diameter of the tube. It is a loose fit, no need for fine tolerances. The spigot is short, only about 1/8 inch long. The thickness of the collar is about 1/8 inch also. It is - of course - drilled coaxially for the Bowden cable. There is also a counter bore for the cable casing ferrule. Deep as practical but not critical as it can be compensated with the cable adjustment. The last feature is an axial slot to allow it to be slipped over the inner cable.



-Doug

Afternoon Tomas
See the attached picture, these people may be able to help you?

Steve