Mk1 Sq 4 Carb

[nevhunter]

Bodies do warp and Jamb but with a four there's almost a continuous suck forcing the slide by about 10 psi and a bit higher nearer idle whereas a single is pulses. That's about half a housebrick weight forcing the slide against the body, unless it's near full open. THAT has to make it's job of sliding harder. Nev

[Paul_Linden]

A Solex 26 FHG has popped up on eBay, which might be suitable. It looks like it has a tickler on the top of the float bowl.
https://www.ebay.co.uk/itm/254612302537

[JohnnyBeckett]

HI That looks OK if was me i would have a go at buying it they do not come up that often and it is handy for parts as well

[simon.holyfield]

Isn't it the wrong hand?

[Paul_Linden]

Yes, the float bowl will be on the left, but I think that’s actually better as it is then not near the distributor.

[T.J.Falloon]

Hi everyone,
Thank you for all your responses. Certainly looks promising and will make a bid, but before I do, isn't the mounting flange in the wrong plane (vertical) instead of horizontal, or is the carb supposed to be mounted on it's side, or am I just looking at the thing completely the wrong way? Apologise for the stupid question.

[john.bebb]

Hi TJ,
Thanks for the jet info.
I too suspect the carb on ebay is NOT the correct device... & I do not see the bi-start mech...
but the flange to which you refer may be rotated to the requisite orientation - it is a square fixture located by four corner screws.
On the Amal front the suggested spring streach preload; - why not make your own "super-spring" in heavier guage piano wire? - just be aware that with a heavier guage wire the compressed length must be equal to or less than the original to avoid coil binding.
Cheers, John

[D.Ryan]

Hi all,
Four years ago I was fortunate enough to pick up a NOS Solex 26 AHD at Bendigo swap meet for $60 AU. The carburettor was originally off a BSA 430 cc stationary engine. I did have to swap the choke tube and jets from my old carburettor to the new one. The choke tube on the BSA is 23mm so either a swap out or turn up a new one with the right bore are feasible.
It might be worth having a look in the old barns and sheds for pump and saw motors, I bet they would be much cheaper than what I see on the net for square four carburettors. Regards Dennis

[chris-diamond]

Hi, Some years ago I also had the thread strip on my solex, I couldn’t identify the thread, I had wanted to use a recoil, I had a word with the turner at my workplace and he also couldn’t find a match, we did find that a 1/2” UNF has the same thread pitch (20 TPI) it is approximately 0.80mm bigger in diameter than the original bolt. I purchased some taps, the carb tapped very nicely, the tap followed the original thread and as Simon Holyfield said there is quite a lot of meat and you can tap a good bit deeper than the original thread was tapped. The Turner then machined me a 1/2” UNF bolt, (see photo of new bolt against photo of the old original bolt) the Banjo and chrome choke plate then needed to be opened up slightly, also a new filter gauze had to be made. I now get a full 15mm of bolt going into the carb, perhaps you could use a M12 recoil and purchase a standard M12 banjo bolt (there are plenty on eBay), it should then go through the banjo and chrome choke plate without opening them up. I do wonder if Ariel’s purchased solex carbs and fitted their own choke cable plate, along with the two fibre washes you are lucky if you get 6 or 7mm thread, I’d be surprised if solex intended such a short thread to go into the carb! although of course you could gain some additional thread by machining some metal off either side of the banjo.
Cheers,
Chris.

[chris-diamond]

Hi, Some years ago I also had the thread strip on my solex, I couldn’t identify the thread, I had wanted to use a recoil, I had a word with the turner at my workplace and he also couldn’t find a match, we did find that a 1/2” UNF has the same thread pitch (20 TPI) it is approximately 0.80mm bigger in diameter than the original bolt. I purchased some taps, the carb tapped very nicely, the tap followed the original thread and as Simon Holyfield said there is quite a lot of meat and you can tap a good bit deeper than the original thread was tapped. The Turner then machined me a 1/2” UNF bolt, (see photo of new bolt against photo of the old original bolt) the Banjo and chrome choke plate then needed to be opened up slightly, also a new filter gauze had to be made. I now get a full 15mm of bolt going into the carb, perhaps you could use a M12 recoil and purchase a standard M12 banjo bolt (there are plenty on eBay), it should then go through the banjo and chrome choke plate without opening them up. I do wonder if Ariel’s purchased solex carbs and fitted their own choke cable plate, along with the two fibre washes you are lucky if you get 6 or 7mm thread, I’d be surprised if solex intended such a short thread to go into the carb! although of course you could gain some additional thread by machining some metal off either side of the banjo.
Cheers,
Chris.

P.S The photo with the banjo bolt going through the banjo and chrome plate is the original bolt with only about 6 or 7mm showing.