SOLEX 30MOV

[Damian GT]

Agree 100% with Tom. Complete pain using a Solex (though some of us have persisted) and getting smooth transition from idle to main jet is tricky.  Found various mods help - including adjusting the position of the progression holes in the main jet tube.  I also suspect the Specific Gravity of fuel has changed over time and those us still fiddling with Solexes have to make do with whichever floats we can get our hands on.  Good luck though, and welcome to the Solex "glutton for punishment' Club.

By repute early GE Brooklands had twin updraft Zenith HK triple diffuser carbs.  Don't ask..


https://www.scienceandsociety.co.uk/resu...=1&itemx=1

[Robert Foreman]

On the D and M types the progression from slow to main can be alleviated with small incremental changes to the slow running jet. 
  I have done this successfully from GN's to big Edwardians.

[tomcotez]

They do look nice though! The best mod I have done is to cut off the tubular part of the jet carrier base and solder on a slightly larger diameter well -  10mm id brass tube will just slip over the stump of the old well if you leave a bit to locate it. This gives a slightly larger reservoir of fuel around the jet to be sucked up when you accelerate and made all the difference on mine. The other option is to avoid using the slow jet by driving at full speed all the time.

[Damian GT]

Yeah. The consensus amongst us 'triers' is that the reservoir well is insufficient for smooth acceleration.  Seems all the more relevant if you use a Solex for competition - an 'on-off' throttle doesn't help if you're trying not to look foolish.  It never ceases to amaze me how little things that don't show up on the road show up instantaneously if you compete in your car.

[tomcotez]

Interesting to hear that, it definitely worked for me but some people seem to get on fine just using the standard range of adjustment. My brother’s car is nearly ready so we’ll see how his works.
City traffic is also pretty good test of carburation.

[Charles P]

They do look nice though! The best mod I have done is to cut off the tubular part of the jet carrier base and solder on a slightly larger diameter well -  10mm id brass tube will just slip over the stump of the old well if you leave a bit to locate it. This gives a slightly larger reservoir of fuel around the jet to be sucked up when you accelerate and made all the difference on mine. The other option is to avoid using the slow jet by driving at full speed all the time.

Harder to do that on a horizontal Solex, but I agree with the thesis.
I do wonder if that's why they increased the size of the threaded base on the jet carrier. My 35MH has the smaller thread and there's simply not enough metal to open it out but later versions (possibly MOH?) are substantially meatier to handle the bigger thread. 

C

[Ncoates]

Charles,

I have managed successfully to convert an MV40 base into an MOV 40 base by silver soldering on a larger lump at the jet carrier boss, and drilling/tapping out to the MOV jet carrier size (think it’s 11mm metric fine). As you say not possible without this type of drastic surgery, but it has proved 100% worthwhile. The problem I had with the MV is that the fuel surged back down the main fuel feed drilling into the float chamber during hard breaking and effectively starved the jet of any fuel, cutting the engine out. I will
Post some photos for anyone that it interested when I get a chance. 

Best,

Nick

[Charles P]

Nick

Good to hear it works and makes a difference.
Photos please.
It may be bravery (or lack of) that's holding me back

Thanks

Charles