(08-01-2020, 09:36 AM)Tom Coates Wrote: Thanks for your contributions. Robert Foreman re-bushed the throttle spindle for me and i have discussed the subject with him at length. The problem seems to be that different people get very different results with ostensibly the same set up .
Given the problems other people have had maybe I'm not doing too badly after all. In my limited experience the key to good pick up is the size of the well in the jet carrier assembly which fills up with fuel at idle speed and lets it out in a big splurge when you blip the throttle - a sort of jet pump effect. There are various different sized assemblies, the details of which do not all of which appear in the solex literature. After a bit of fiddling I have now got it set up reasonably satisfactorily and will possibly need to make a new jet cap to replace the one on loan from my brother which is the bigger size and seems impossible to find.
Part of the trouble is city driving, on the open road the pick-up and idle mixture are less crucial, but now i have my car in Paris i spenf a lot of time at traffic lights and driving on part throttle which magnifies these problems. I am thinking of getting a lambda sensor to try and make the tuning process a bit more scientific...
I think you're right about the "well". John Howell in his article on carbs for vintage racing cars highlights this. Later carbs, with the bigger main jets have more scope here than the earlier ones, where the casting in the carb may not accommodate the later, bigger jet carrier. Narrowing the OD of the jet may help.
Like Damian I found that on the 35MH I got a reasonable balance of mixture across the range only by soldering up and redrilling the bleed holes (another Howell tip) in the jet but it's a painful trial and error approach with a lambda. Still not perfect and the main jet is bigger than the Solex "ready reckoner" would suggest.
Charles