double carburetor idea?

[benjammer112]

alright homies, i got a terrific idea, i have like 4 or so carburetors lying around, plus the one on my honda urban express nu 50, here's my idea, take the stock intake manifold off, adapt a custom made aluminium one, and attatch 2 carburetors to it! sounds like a good idea! and i might even port the exhaust port. AND i might mill the head down just a tad to raise compression, i think i would have one screaming moped. GIVE ME YOUR THOUGHTS MY CHILDREN

[z50r-ghost]

.... I never like to be negative bro, but there's probably a reason that not many people have tried this. -if you go to YouTube, search "diospeeddemon" (giggle-giggle) and check out the 2-carb setup he attempted. I'm thinking it didn't work.

I'm not a carb expert by any means... But there us a guy here who has more 2 stroke carb knowledge than most of us combined.
-Maybe he can explain why the twin carb idea might not be beneficial.

I'll try to call him now: GRRR-GRRRR-GROWL.

Later man, j

[SuprasNsprees]

Sweet.

Just Add another engine , and you're in there like swimwear

[Bear45-70]

Actually in the real world two multiple smaller carbs are better than one big one. A carb engineer at a race told me that "A lot of little holes will out preform one big hole ever time for all around performance". The problem here is throttle linkage because a progress opening would be better than both opening at once.

[Wheelman-111]

Greetings:

Adding Carburetion will only increase performance if a lack of carb was the limiting factor at the start. The stock carb is a 14mm venturi, admittedly small. However an increase to a 17.5 or 19mm is more than enough to address the issue. It does not follow that doubling up the carbs will add any performance.

So,
Aside from the need to make a manifold, find a place to put the Twin, split your fuel supply, link up the throttle and the Nightmare that should be "Tuniing" this beast, then yeah, it's totally worth it.

[Bear45-70]

True to an extent, but two smaller carb bores are easier for the motor to deal with than one big one.

Real life example;

428CJ came stock with a 735 CFM (a maximum of 735 Cubic Feet per Minute air flow) with vacuum control secondaries carb. Vacuum secondaries open only when the engine needs the additional air, just like the CVK carbs do.

Car and 13.88 at 102 mph in the 1/4 mile.

Changed to 920 CFM 3 X 2 barrel system, all throttle valves were mechanical. When you stomped it to the floor the engine saw 920 CFM of carb.

Car ran 13.55 at 104 mph.

Changed to a 1200 CFM 2 X 4 barrel with vacuum controlled secondaries.

Car ran 13.72 at 106 mph.

This shows that the engine liked the 3X2 best for acceleration but the horsepower was higher with the 2X4.

A lot of little holes is good, up to a point. Too much of anything is bad.

I think finding a pair of 12 mm carbs off the 1983-84 Aero 50 would be killer.

[benjammer112]

interesting point, but it wouldnt be to difficult for me to grind and aluminum piece for the manifold, i have a nice chunk that would work great. and i have oodles of throttle cables "split for oil injections" so if i could just run another split cable to the current split one, i would have 3 throttle hook ups, i could make one carb adjustable, as in the cable could have slack in it till half throttle then the second carb would open up, or adjust it to an optimum setting. i think i might try this.

[Bear45-70]

Your linkage idea will not work. With the same cable movement both carbs either open at the same time and reach WOT at the same time or one carb will never reach WOT. You will have to create some sort of linkage to make the second carb open faster than the first if you delay it's opening.

[z50r-ghost]

My abused "brain" is learning new things here... Great stuff I never knew or even imagined...
Thanks for your input Bear-dude...

-j

[eliteguy50]

Your linkage idea will not work. With the same cable movement both carbs either open at the same time and reach WOT at the same time or one carb will never reach WOT. You will have to create some sort of linkage to make the second carb open faster than the first if you delay it's opening.

An inline spring in your primary carb's throttle cable or using a slide carb and a cam secondary.