Solex carburettor

[will_curry]

The one shown in Pete's picture - the 'real thing' - can jam in the cable attachment at the
butterfly end and allow the butterfly to remain partly open, another good reason for
relocating the ignition switch in the headlamp where it is less difficult to reach.

I've threaded a small washer over the nipple to sit between the spring and the attachment
to good effect in the past.

[cbranni]

My involute spring was a little lazy, no amount of fettling could get it right so I added an extra spring and it now works perfectly may not look very nice but it works.

Kind regards Colin

[Pete.Silson]

My previous picture was of the carb as originally dug out the shed however...

This picture above is the same spring on the 4G now. The bracket is at the correct angle to keep the spring straight with the throttle closed. In order to prevent the spring jamming on the cable there was a small sleeve (A) on the bracket at the fat end of the spring plus I put a small brass insert inside the thin end (B) so, by this means, the cable stays concentric to the spring at all times. I also used a barrel nipple (as opposed to the ball in Colin's picture) which keeps everything nice and square. It all seems to work smoothly and without incident.

The bracket listed by Drags (1024A-37) seems to be different from the one on my 4G so maybe the Mk1 bracket is different. Similarly the spring (6492A-37) in Drags is tapered at both ends and wouldn't work on the arrangement on my 4G. Both the bracket and the spring on my 4G are 1946 factory original parts.

[paul.jameson]

I have never had a single taper volute spring like Pete Silson's as both mine have been from Drags and symmetrical. I don't recollect ever having a problem with them beyond a tendency for the butterfly to remain very slightly more open than I would have wished. Curing this is a matter of getting the cable straight as Pete says. I did around 27,500 miles on my two 4Gs in total.

[klaus gerhard]

I have the same experience as Colin. I fitted an extra return spring and now the butterfly closes perfectly when idling!
Regards Klaus

[malcolmm]

Thanks everyone for your input it’s a lot clearer now I need to start making a bracket.
Thanks Malcolm.