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Solex AHD 26 - Low speed jet

Posted: Sun May 03, 2026 2:46 pm
by camstevens
Hi All
My Solex is deciding to play tricks on me again.....classic symptoms of a blocked low speed jet (number 70). Starts no issue on choke, but will only run at higher revs with choke in. Push the choke in at idle, splut, dead. So, just stripped and cleaned and hopfully caught the issue.

I have a question (maybe a nieve one), but I was curious as to how the low speed jet stem seals effectivley once fitted to the main body of the carb.....the low speed draws its air from the little aperature that leads to the main air intake, but fuel drawn from the 70 jet direct from bowl. But...my question is whether air can leak around the jet stem and whether it is known to cause issues. It would certainly expalin some of the behaviors I get when the engine is hot and coming down from road speeds. The lower photo shows the jet stem just as it is entering the carb body.

C
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Re: Solex AHD 26 - Low speed jet

Posted: Sun May 03, 2026 8:58 pm
by simon.holyfield
I've always assumed that because the annular air gap around that jet is constant, then the jetting arrangement must be able to cope with it.

I can't offer any more than that, but I agree it seems odd. These are commonly used carburettors in the automobile world though.

Re: Solex AHD 26 - Low speed jet

Posted: Mon May 04, 2026 6:55 am
by camstevens
Thanks Simon
They are a pretty simple setup, so one would think an issue could be identified easily. If you recall the paper gasket issue (blocking hole), the gasket has gone as hard as teak, so possibly passing air. Will replace