Removing Solex carbs and replacing with webers

[burnzdog]

Hi All,

Decided to remove the old and failing solex carbs and replaced with some dual webers. All running well but im now left with a few pipes and holes which were part of the various vacuum ports. In the pic below shows a few pipes are not sure what I should do with now. The distributor also has two vacuum leads coming from it? I know ones for the advance but not sure what the other is for?

IMAG1175.jpg

[sarran1955]

Hello,

Since you have changed the carbs..(manual choke??)..

Fit a new dizzy and get rid of the old 'Hall effect' system..

Like this:

https://www.youtube.com/watch?v=KkyBAMMHpa4" onclick="window.open(this.href);return false;

From your photo..

The middle oval is your crankcase breather.. which could be connected to the underside of your shiny pancakes.. if they have spigots..

Otherwise fit a scooter filter and clean regularly.,

Right hand hole was for your air intake.. remove it and snap fit the lid off a jam jar in place..(your choice of Jam}..

Hope this helps..

Cordialement,

[Simon james]

Which webers did you use ?
Are they any good
Thanks simon

[Bubble Meister]

Sarran, why would you recommend getting rid of the dizzy? Assuming the dizzy is standard and that the vacuum unit is serviceable, it is designed for the baseline performance and is bespoke to that engine type. Therfore advancing and retarding correctly.

[djaychela]

Hi All,
The distributor also has two vacuum leads coming from it? I know ones for the advance but not sure what the other is for?

IMAG1175.jpg

The second vacuum connection is for retard at idle - it changes the timing from ~7.5 deg BTDC to 5 deg ATDC at idle - this gives much better emissions performance at idle. It's driven by a vacuum signal which is only present at idle, which you may or may not be able to engineer on the carb conversion that you have; if you have a vacuum take-off which is on the engine side of the throttle butterflies then that should provide a suitable signal (high vacuum at idle, but dropping off when the throttle is opened). Just got my CU set up properly using this and it works really well, but getting the right vacuum signal is crucial.

I'd second Bubble Meister's question (not to you) - why would you want to replace the distributor? It has the right vacuum and centrifugal advance curve for the engine, and not sure why you'd want to get rid of the electronic ignition either, works perfectly well when it's working as it should do!

[sarran1955]

Hello,

Sarran, why would you recommend getting rid of the dizzy? Assuming the dizzy is standard and that the vacuum unit is serviceable, it is designed for the baseline performance and is bespoke to that engine type. Therfore advancing and retarding correctly.

If you are going to all the trouble of overhauling the carbs, or even changing them..then why not for the price of a new hall sender, replace the 40 year old ignition with a modern dizzy and coil..time at 8 or 9 btdc..

Like this:

https://www.youtube.com/watch?v=KkyBAMMHpa4" onclick="window.open(this.href);return false;

Just 1 less thing to go wrong..

Makes no difference to emissions..the whole atdc thing is entirely due to the hall sensor (well more or less)..

Or you can be real heretic.. and go for £10 off ebay genuine Bosch points and condensor dizzy..

Like this one we did a few years back:

https://www.youtube.com/watch?v=4qayyc9Z4E0" onclick="window.open(this.href);return false;

then:

https://www.youtube.com/watch?v=dsfo5ATgBp0" onclick="window.open(this.href);return false;

Note original carbs and note emissions on the meter..

Just my point of view.

Hope I've answered your Q..

Cordialement..