Solex Jetting Changes for 1953

[simon.holyfield]

Folks,

I'm sure most of you will have gathered over the years that I'm quite a fan of the 26AHD on my SQ4, and also that in common with a lot of you I like to tinker with stuff.

Here's one. Has any noticed - I'm sure you have - that Ariel changed the pilot and air correction jets for the 1953 season, to make the bike run leaner over the rev range?

I'm going to see if I can find the appropriate jets and see what happens. My bike has always run rich, better since adding additional washers to the float valve. It would be interesting to see if anyone has been there, done that before.

[Chris Sealy]

Hi Simes. I am also a Solex AHD fan. I have been restoring, and playing, with them for more years than is healthy.
The first thing that I would suggest is to set the fuel level. It should be level with the bottom of the air intake; although plus or minus a millimetre makes little difference.
Unlike earlier Solex carbs; The AH and FH are easy to tune, because the main petrol jet affects the richness more at the smaller throttle opening; and the air correction jet affects the richness more at larger throttle opening.
The picture shows how I check the fuel level using a modified main jet holder. A spirit level is put across the top of the float chamber before the rest of the carb is attached using the two screws.
Cheers, Chris.

[paul.jameson]

I have always believed that the change in jets for 1953 was because of the introduction of the Mk II engine that year which has, of course, rather different characteristics (such as compression ratio) from the Mk I.
1953 is the only year that the Mk II was fitted with the Solex carb.

[simon.holyfield]

I have always believed that the change in jets for 1953 was because of the introduction of the Mk II engine that year which has, of course, rather different characteristics (such as compression ratio) from the Mk I.
1953 is the only year that the Mk II was fitted with the Solex carb.

Thanks Paul. I hadn't spotted that one - I'll go and look at the parts books to see if the last Mk1s had the jet changes as well.