flat slide throttle motorcycle carbs on car engines

[Rota_Motor]

hmm, interesting thing, motorcycles carbs being sidedraft,
how about setting up quad carbs on a 12A or 13B, one per inlet port,
with the compact size of the carbs, Im sure they would fit between the engine and the inner guard/strut tower,
giving an extremely short inlet tract, and very good throttle response?

but then you would need to balance them all again, which could be a problem as said.

[Zac]

jasondale, Keihin carbs?

[mondo2000]

Rota_Motor:

Primary and secondary ports on a rotary are different sizes and flow different amounts, so at the very least the carbs would have to be jetted differently.

Also, mounting them close to the ports would put them right above the exhaust, allowing the fuel to boil nicely in the bowls.

Balancing quad carbs is no problem. Use a carb balancer as Chipper pointed out.

floody: Isn't the Honda CBX 6 cylinder 1000cc? Both the CBX and the Z1300 probably make less power than a modern 600.

[floody]

I think you are correct about the cbx mondo2000 . I don't like old hondas,so I don't know anything about them, that and the fact they sold jack all when new means I've never seen one in the flesh, unlike cx500s which are stacked 4 high in the workshop daily..... The old 1300's didn't rev real high, but they were pretty torquey, i'd wager the torque numbers would be a different story.
Goddamn those z1300's sound EVIL!!! if the zed sounded lik a 1300 kwaka with an exhaust system, it would be worth the hassle!!

On the boiling fuel in the bowls thing, You would need a good heatshield above the exhaust manifold in the zed, or an LY24 head....

Keihin and mikuni both make quite a range of flatlides, most modern hi po 4's have a SEMI-downdraught setup, but something will be available. I'd steer clear of lectrons, personally, but I've only messed with 1970's examples which were average, but better than bing's, amals etc....
cheers,
floody

[floody]

Also, I remembered the brand of carbs that have the best features of dellorto/weber sidedraughts combined-they are supposedly american (though once out of the box the ones I saw had made in japan cast on them)-and are called "SK" I think.
cheers,
floody

[roastbeef]

still havent been able to find much detailed information on this process..
but did discover a few production cars which use Keihin FCR's.

Tommy Kaira ZZ
using a n/a Sr20de and quad 40mm keihin FCR's
it manages to squeeze out 197hp.
There are apparently problems with fuel delivery at high rpm though.

The honda s800 also used motorcycle carbs.

[CnC]

Sounds like you are going to a hell of a lot of trouble for no reason. Just get an EFI setup and be done with it.

[Zac]

Just had to go ruin a perfectly good thread didn't you CnC!?

[Warpspeed]

CnC is right !

Anything with only two wheels is an instrument of the devil, as are all carbies.

[Zac]

Stay outta this thread then.

[Warpspeed]

On ya bike zac, go and play in the traffic.

[jasondale]

Modern Lectrons or FBG's are the carby of choice for most drag bike racers, easily adjusted, they are awesome for power!! Problem is cost 48mm's would be ideal though.

[Rota_Motor]

mondo2000: I realise primary ansd secondary ports are differently sized, but, if all four were jetted the same, one would run lean and one rich for each rotor, and due to the turbulence the mixtures would be evened out by the time they were fired. well it works for 12AT's which only have one injector in the primary port only.

as for the fuel boiling in the bowls, I have seen a sidedraft weber mounted directly above the exhauist, and with a decent heatshield, there was no problems. also could use ducting to provide airflow between when moving which is when most heat would be a problem.

could be worth a try anyway. have also thought of a single carb feeding both primary ports, and a linkage setup to have one carb for each secondary open up above say 2/3 WOT.

[Zac]

If I wanted to know how great EFI is then I might have started a thread called '1000001 reasons why EFI is better'..
This thread is about carbs, simple really!

Edit: before you try and can me again, I know EFI is better, I'm not stupid. But I am still interested in carbs. This thread is about carbs.

[hemi770]

Warpspeed-

Nothing wrong at all with a good carby setup. If you actually knew what a good carby setup is like, I can't see why you'd be bagging them out.