In the what if ? series

[Caen Fred]

:stupid:

I was looking at my bike the other day and a spark lighted my already burning head. What if I put 6 motorcycle carbs on a triple carb manifold? Why do motorcycles have one carb/cyl and not cars? They are very inexpensive around here and a lot of sizes are available ? Ever been done ?

Fred

[ozlime240z]

Originally posted by 2ManyZs

Main reason is that the motorcycle carbs would never flow enough cfm to fill a combustion chamber on an automotive engine. They just aren't big enough to flow enough air and fuel to fill a combustion chamber that large. Motorcycles have such a small bore and stroke compared to an automotive engine is the one reason they can get away with it.

Interesting point, but I have a Honda XR 600 sitting in tha garage here which is a single potter. That's 600cc in a single cylinder! An L24 only has 400cc per cylinder! (2400/6=400) So I don't think this point is valid. Put 6 carbs off the likes of a hy-po Honda CR-600 road bike and I think you will have more than enough flow.

Some Moto-Guzzi Bikes in this country (Australia) where fitted with 45MM dual barrell Delortos (1 of). Same carb as what where fitted to some Fiats (2 of), Ferraris (4 of) Lamborgreenies(6 of) and my Z! (3 of) So bike carbies are often no different. Especially on hi-po road bikes.

This mod would work as long as the barrels where big enough, I'm thinking 40mm for an L24. The throttle linkage could be a nightmare, six balances! wow.

As long as jetting is available to allow proper tuning, the barrells are big enough, and they are side-draft. why not!

Originally posted by 2ManyZs

3 two barrel Webers on a Z engine, or 4 two barrel Webers on something like an Aston Martin Vantage V-8 works fine.

6 Bike carbies from a wreckers would be signifigantly cheaper than three Webers these days. I love my Delortos but they haven't been made for 10 years or so and the price keeps going up. Good for me I guess, since I already have them. Luckily they still seem to be making parts.

Bike carbs could work out to be a cheap speed mod for someone willing to spend the time to set it up. I say go for it!

OzLime240Z

[ozlime240z]

Originally posted by Caen Fred

Why do motorcycles have one carb/cyl and not cars?

Simple. Much lower emissions standards. Motor Bikes don't have Catalytic converters either!

Motor bikes are also (generally) a hi-performance item. They are light and if they us allot of fuel for their size no-one seems to care. They still use less fuel than their car and go quick as!

OzLime

[Caen Fred]

Merci you both, my French practical sense make me think that if it never have been done before, it doesn't mean that it's not worth trying (very rational, hee?).

Maybe I will try this test "new mod" in my free time.

[beandip]

and if you install a tripple you have one per cylinder . So it has been tried and is common.

[Z-point]

Did it already. One of our members had 6 carbs from a GPX 750 bike on his engine. He wrote in 1999! in our magazine "he had trouble with backfire at 3000rpm.He tried big and smaller needles but at that time nothing worked” end of story.

You want me to check this up?

your are lucky I saved all pictures from our magazines

[HS30-H]

Hi Fred, Guus, 2Many, ozlime, beandip and everyone,

Like so many things, its been done in Japan before. You used to be able to buy a kit for quite a lot of Japanese "Classic" cars - although it was pretty expensive.

The FCR carbs cured all the tuning problems that Guus mentions, and I believe that they work quite well.

The following pictures are of C10 and C110 Skylines with the 6 FCR's on L28 engines. Sorry I could not dig up any S30-series Z pictures with the FCR's.

Alan T.

[HS30-H]

Pic. 2:

[HS30-H]

Pic.3:

[HS30-H]

Pic.4:

[Caen Fred]

Sir Alan, you have been promoted to the rank of Azmiral or our fleet.

You have such a broad firepower, every time I think I will nail you... you come up with a pertinent response! I give up (no don't worry I will use you data base again, I want to know if it has an end? I am an human, as for you I start to doubt ! still not sure about angel or demon... :classic: :devious:

Well This look awesome, almost like inside a Swiss watch, and some found that a 3carbs set-up look busy!!!! So there is a kit, is it for the manifold and linkage? from what you say they didn't used it for an economical issue?

Well, merci, merci again.

[Sean Dezart]

Alan,

your photos beat the hell outa pornography anyday!

I really want to fondle those air filters!!!

Jeez, if I could just spend an hour in your photo library...