square 4 carb conversion

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william shortall
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square 4 carb conversion

Postby william shortall » Mon Oct 05, 2020 4:41 pm

I have been informed by dragonfly that they do not do the concentric conversion for my square 4 which is a twin pipe alloy engine 1952 in a 1956 rolling chassis .
Has anybody got any idea if this can be sorted or can i get a gasket set for the solex
many thanks
Bill Shortall

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Paul_Linden
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Re: square 4 carb conversion

Postby Paul_Linden » Mon Oct 05, 2020 8:35 pm

Bill, to refurb the Solex there are 3 fibre washers (2 on jets, 1 on float valve) and one square gasket for the choke block, which is easy to cut by hand.
As others have said, a correctly setup Solex is a very good carb, while the Amal is much harsher. If you really want an Amal concentric for your mark 1, then send me a private message via this forum.
Ariel Square 4 mk2, Ariel Square 4 mk3 (yes, really), Ariel Colt, Matchless G12, BSA C12. Room for one more......

william shortall
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Re: square 4 carb conversion

Postby william shortall » Tue Oct 06, 2020 7:52 am

Many thanks i will tyr the solex and if i have any problems i will get in contact.
i have had it ultrasonic cleaned so i will see how i get on ,is there a set up procedure in the manual

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john.bebb
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Re: square 4 carb conversion

Postby john.bebb » Thu Oct 08, 2020 5:17 am

Hi Folks - Paul - we'll agree to differ on opinion of the Solex...
As far as I'm concerned ditching the Solex is one of the top 3 mods I've done to my MK1 Sq...
(others being to ditch the Lucas 6V 70W dynamo for the Iron Horse 12V 300W alternator
& to ditch the pathetic excuse of a front brake(?) for the 230mm 4LS Grimeca).
William - as you've got a Mk1 Sq in a later "dog-legged" frame you've plenty space to fit (almost) any carb you wish.
The Amal which Drags supply is a Mk1 626 - modded to fit the narrower stud spacing as on the Sq's head flange.
Quite why they supply a 626 is beyond me as the Mk1 Sq4 induction bore is only 22mm.
This leaves a 2mm peripheral doorstep for the gas flow! (Paul; - no wonder it's "harsh"!)
I've belled (via a conical cutter) my Sq's induction tract to flow appropriately...
but surely it would be more sane to fit an Amal 622 which has similar bore size to the Sq?
Use of an Amal may cause slide stiction, there are two reasons for this:
1/ the carb has been overtighted - (Amal spec) you should be able to slide a minimum 0.025" feeler gauge between flanges.
2/ the carb was not designed for multipots which give a far more constant suction than a single.
Amal do not make stronger return springs (see other threads)...
Cheers, John

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Re: square 4 carb conversion

Postby T.J.Falloon » Fri Oct 16, 2020 3:18 am

Hi Paul,
As a matter of interest which jets have the fibre washers? I don't think my carb has any fibre washers except the one for the needle valve.
Also, is there a manual for the carbs anywhere? Thanks.

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Re: square 4 carb conversion

Postby Paul_Linden » Fri Oct 16, 2020 5:38 am

The starter jet (GS), main jet holder, and needle valve have fibre washers. The first two are located at the bottom of the float bowl.
Info on Solex carbs is on the Draganfly website and the online archive for club members. Here is a useful diagram of the 26AHD.
62788CAD-BEC6-41B8-8681-A7AECB88B2C7.jpeg
Ariel Square 4 mk2, Ariel Square 4 mk3 (yes, really), Ariel Colt, Matchless G12, BSA C12. Room for one more......

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adrian.hannam
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Re: square 4 carb conversion

Postby adrian.hannam » Fri Oct 16, 2020 8:44 am

When you replace the starter jet washer, observe the cross drilled hole in the jet is fully open to the well. I used two washers for mine to be unobscured. Not sure it makes a great difference, but when I was having trouble with cold starting, it was one of the things I fixed.
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william shortall
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Re: square 4 carb conversion

Postby william shortall » Fri Oct 16, 2020 9:31 am

Thank you what is the script with the air filter mine has none

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simon.holyfield
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Re: square 4 carb conversion

Postby simon.holyfield » Fri Oct 16, 2020 10:51 am

Mine doesn't have one, just the air bell.
cheers

Simes

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Re: square 4 carb conversion

Postby Gui.dorey » Fri Oct 16, 2020 11:32 am

Mine also does not have an air filter.


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