Hi there,

I guess in the UK there is a lot more experience with setting up double carbs then over on this side of the pond, so I thought let's try posting this over here! (and in general you guys are much nicer not whining all the time 'keep it original' 'the car is not made to go fast' etc )

ok, below is my setup right now, and it is running like shit! I got the carbs second hand from a guy who used it on a visa engine himself, he got 47 HP out of it on a rolling road! tried the setup he used on my car, but for some reason it doesn't run well, so I took the carbs apart and noticed: different floats, different emulsiontubes, different main jets... all slight differences, but still. so I don't trust the settings of the carbs at all, and want to start over again!

Visa engine
Visa 630 (fastest stock) camshaft
new cylinders, and pistons (CR 9.5)
12-spark
2 Dellorto 30 mm carbs (PHBH)
home made inlet manifolds, nothing special about that.
it will have a 'forced air' inlet; a.k.a. turbotube, but want to achieve a setup without that first.



questions:
- does anyone know what the standard setting (jet sizes etc) would be for this setup to start tuning from?
- some say a fuelpressure regulator is needed (I'm using the original pump), Do I?

hope someone can shed some light to this mystery (to me it is)!

greetzzzzzzz, Rusty

Thinking about your double setup..

'First a question.. when the other guy gets 47hp out of an engine why has he sold it to you?? I would cherish it and never sell it.. So this is already something I wont believe, strengthened by the fact that you have 2 very diffrent carbs as I understand it...

I don't know the standard setup of your carbs...



I would start with a standard VISA/2cv manifold with 1 Visa/2cvcarb.
(sorting 1-2-spark pickup place if neccecary)

If this runs well go back to your double carbs setup..

Now what I'm going to tell no is very wrong but...

Put 1 sparkplug out take the carb of that side of the engine and let the engine run on just 1 carb till it runs fine (well as fine as it gets on 1 cilinder).

Then change the carbs and look if you can get the engine running like the first carb.

Then put in both carbs and plug and it should be fine then..


p.s. Is your throttle-linkage spot on??? or is 1 carb opening faster then the other, please bouble check this....

p.s. 2. On my Beamer engine I was very positive surprised how easy the 2 2cv carbs are running the engine.......

succes...

When I ran my Visa engine with 2 amal carbs it took time but was great in the end. You will need a carb balance gauge - so they both are equal at tick over and then open together at the same rate. As for insides - you need both with the same jets etc - do not know how he ran his with different jets etc (strange)
I bought lots of needles etc to get it spot on _ lucky for me I based my carbs on a Royal Enfield 350 cc single so worked off that with the idea that the Visa engine was just like 2 -350cc engines bolted together

The other thing with my set up was the pump as the amals did not have strong enough float valves to stop the petrol from the pump so over flowed - I had to made a little tank with a return to the tank and then it gravity fed the carbs - worked then

thnx for the reply!



he claimed that he ruiined his whole front suspension, but in the end I found out he overrevved his engine, so destroyed his valves and pistons. also the car used about twice the amount of fuel it used to do with original visa carb.

and the carbs are the same type, there were just different parts in it?! but I also got a big box with several jets and other parts, so the setup is the same now!

I got a printout of the rolling road he went on, so it is not just a false claim.



tought about that but I also have a Lambdasensor (14point 7, LSU 4.9) which I can screw into each exhaust. so I should be able to get the settings right with that!



ah, yes this is a thing, I have a balancer (got it with the set) just not really got to setting the 2 carbs exactly the same! this ist the first thing I will do tonight/ tomorrow!

Got a balancer with the carbs, so that will work just fine, and the floats seem to be ok, no flooding whatsoever!

This evening I changed the needle and setup the idlemixturescrew, also set the carbs so that they open at exactly the same time! And now it is running great, it is real fun to go for a drive without doors and fenders and the engine running well! It pulls well in all gears (amisuper gearbox) just needs quite some finetuning. But will get to that tomorrow!

Thnx for your help!

Please a youtube video...

+1,or some still photos at least!

And you do know you should keep it stock or even retrofit a 425, these cars cant handle the speed y'know

Are you sure these carbs can work with a forced are intake?
Maybe a slight necessary pressure difference is not there and the carbs don't work the way they are designed for.
Just a thought.

yep id ditch the "Blower" they can upset carbs - re introduce it later when its working, some bike carbs use gravity to fill the bowls therefore the float valves are weak.