Individual carbs

[Christ]

I mentioned some time back about putting IC's on my other Festiva if I couldn't get the EFI running correctly with relative ease... But I got it running, so I'm gonna leave it. That car is also the eventual recipient of the VW swap, so I'm not playing with it much.

However, the Festiva that I just bought from HondaSlayer is 5 speed and already carb'd, and in need of a good carb cleaning as-is. It's easy enough to set and tune in IC's for me, since I'm used to working on bikes, but does anyone know:

1. What diameter are the intake runners at the head?

I'll probably use carbs from a 600cc bike engine and tune them in accordingly, but the main jets should already be enough for a 6kRPM 1.3L... I'll have to ream the idle jets up, though, because they're likely to be undersized.

I really need to know the runner size so I can pick carbs w/ the right throat size to kinda match 'em up.

[Christ]

If the ports are close-ish to 30mm, that would be perfect. It's a pretty standard carb size for 600cc bikes.

[bravekozak]

I smoothed my runners out to an inch and a quarter. My headers are also an inch and a quarter. Gasket match.

[Christ]

If that's the case, the 30mm carbs I have will fit perfectly!

Sweet when things just "work" like that.

[Advancedynamix]

First, I love this. Second, Make sure that you pay close attention to the stock carb angle on the bike and duplicate this when in the car. That is the single most common mistake that I have seen (this is a common mod on sandrail engines). Being a bike technician I have no doubt that you already know this, but it will really screw up your jetting if the fuel level and angle is incorrect. (FZR carbs are almost straight up, but CBR carbs sit almost level).

[jmye1524]

Just use a 40mm Harley Davidison CV carb setup like this and you'll be very happy. Its a popular setup for Suzuki Samurai rock crawlers knows as the My-Side. ( stock motor is 1.3 )

[Christ]

Just use a 40mm Harley Davidison CV carb setup like this and you'll be very happy. Its a popular setup for Suzuki Samurai rock crawlers knows as the My-Side. ( stock motor is 1.3 )

What's the fun in that? I like the screaming rev sound from the IC's LOL.

[jmye1524]

[Christ]

Much better.

One problem I've already run into without even thinking about it is the 1/2-3/4 spacing. I might have to cut an EFI manifold and have someone weld on some tubes to the correct spacing for the bank of carbs I wanna use.. that could put a serious damper on this. :/

[jmye1524]

Something else to look at.....
http://geckocycles.com/samurai_products.htm

.

[htchbck]

Much better.

One problem I've already run into without even thinking about it is the 1/2-3/4 spacing. I might have to cut an EFI manifold and have someone weld on some tubes to the correct spacing for the bank of carbs I wanna use.. that could put a serious damper on this. :/

I've got a couple spare EFI manifolds you're more than welcome to one for the cost of shipping. I can go ahead and remove the upper plenum to make it easier/cheaper to ship. All I ask is lots of pics! I want to do this too at some point so I'd love to see someone with a little more experience on bikes than I have doing this!

[bravekozak]

There is hardly any room in these small engine compartments. I had enough of a challenge with a twin carb setup. Good luck squeezing in four carbs and then balancing them.

[Christ]

Something else to look at.....
http://geckocycles.com/samurai_products.htm

.

Didn't cost me anything close to that to put GSXR 1000 carbs on my Honda... literally, about $200 for the carbs, $100 and some time for a complete rebuild, and hand drilling the jets to work, then syncing the carbs.

I cut a stock manifold and used rubber boots and aluminum sleeves bonded into the runners to connect the carbs to it, and the spacing was already correct enough that I just pretty much pasted everything together and started the car, then tuned it in over a few days, paying attention to power surging and lean spots.

[Christ]

There is hardly any room in these small engine compartments. I had enough of a challenge with a twin carb setup. Good luck squeezing in four carbs and then balancing them.

I'm considering a very long-runner intake setup using the stock lower intake and a custom upper plenum, which I can basically make myself by bonding the correct tubes to the upper flange and setting the spacing that way, bringing the carbs to the front of the engine, over the exhaust manifold, similar to how the stock intake tubing is run to the throttle body now. As it sits, there's plenty of room at the back of the engine for a set of bike carbs and low-profile filters. Reaching the pilot screws from above the engine bay would be a bit of a pain, though.

The seriously long-runner design will afford more low-end torque, but take away some of the immediate throttle response one would expect from an IC/ITB design. Still, even for the more balanced engine dynamics, it'd be worthwhile.

The nice thing will be if I can tune it to still get 45+ MPG and be ultimately as-driveable or close to it as the original setup.

[Christ]

I've got a couple spare EFI manifolds you're more than welcome to one for the cost of shipping. I can go ahead and remove the upper plenum to make it easier/cheaper to ship. All I ask is lots of pics! I want to do this too at some point so I'd love to see someone with a little more experience on bikes than I have doing this!

For my current thought, It'd really be the upper I'd be interested in, and basically only the flange and an inch or so of tubing. That should ship in a medium FRB, no?

As with everything I do, this'll probably take awhile to complete, since it's not going to be nearly as easy as it was on my Civic the first time I did it. Lemme fix the wheel bearing and stuff and get the carb'd car on the road first, then I'll start figuring out how to paste everything together and make it fit under the hood.

If you're more interested in doing this with an EFI setup, you can probably use the entire electronics including CDI from a bike, using the distributor as sort of a trigger instead of a distributor. Provided the bike's electronics expect grounding from the trigger switch, each point of the distributor can act as a "fire" command for the individual coils. I've never actually tried it, and it's not something I'm prepared to do, but an idea I've had for awhile now.