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solex carb and black smoke .

Posted: Wed Oct 07, 2020 7:48 pm
by GuyWalton
So i wrote this on another post but thought i would start a new thread under the solex title for anyone that may have a black smoke problem .

I had a problem with my solex that i struggled to get to the bottom of . It was excessive black smoke and obvious rich running . No end of searching found very little advice . After setting my gold star float height on the remote float it dawned on me that there was no information on float height on the solex . I took it apart , again , and added an extra fibre washer under the float valve , therefore lowering the float height it was better . A further washer , making 3 , approximately 3mm and it is much better , no black smoke , I still need to ride it but it looking good .

Re: solex carb and black smoke .

Posted: Sat Nov 07, 2020 6:37 pm
by pauldridge
Hi Guy,
I also have a Solex on my '53 MK II Sq 4. Although I haven't seen much black smoke, my plugs do indicate a bit rich in running. My most obvious issue though, is that if I park the bike on its side stand, fuel dribbles continuously from the bowl.

Could you provide details on the size of fiber washer you used underneath the needle seat, and possible source?
(I'm) PM'ing you as well)

Re: solex carb and black smoke .

Posted: Sun Nov 08, 2020 1:10 am
by nevhunter
Float level does have an effect on idle mixture. IF you can't get a suitable thick fibre washer make one of soft aluminium. Nev

Re: solex carb and black smoke .

Posted: Sun Nov 08, 2020 6:43 am
by simon.holyfield
nevhunter wrote:Float level does have an effect on idle mixture. IF you can't get a suitable thick fibre washer make one of soft aluminium. Nev
That's a good idea Nev, thanks. 3 mm sounds like a lot of thickness for a single fibre washer.

Re: solex carb and black smoke .

Posted: Sun Nov 08, 2020 10:12 am
by john.whiting
These carbs are direct needle contact,so a 3mm washer only lowers the float level 3mm.

Re: solex carb and black smoke .

Posted: Mon Nov 09, 2020 1:36 am
by nevhunter
ALL wear in most carburetters makes the mixture richer . I've had to manufacture needles and new seats for the early Schebler HX types as they run extremely poorly with them in worn condition. They are pivoting linkage types and are far more trouble than direct action.. The erratic needle response makes the mixture vary with far more effect than many would think. Nev