Anyone ever thought about using motorcycle Carburetors?

I was thinking about doing something different on 68 C10 and possibly my 37 Pontiac for induction...and the old Webers and Solex setups are getting WAY to expensive...so I started thinking about motorcycle multiple carb setups!

They are cheap..and if I am correct in my thinking will provide enough fuel for a mild 350 setup...I know that a mild LT1 engine uses dual 58mm (larger than stock) throttle body which is 4.56 inches of opening..and an average 4 carb motor cycle setup is quad 34mm openings, which is 5.98 inches of opening...so wouldn't it work?

What do you guys think?..or have I been breathing in to much carb cleaner?..

 

People Use Sidedraft Webbers All The Time. Not Sure If It The Same AS A Motorcycle Carb.

 

Back when we were planning to run a 235 or 302 in our HA/GR car, we were gonna run side-draft Mikunis or something similar. Also, I have a Datsun 240z and have often looked at the nice SUs that it has amd dreamed of polishing them up and running them in a rod. Unfortunately, my current project motor (Olds 371) has way too many cubes to be fed by anything short of A LOT of these carbs. It sure would look cool though...

 

Yeah..that's what I was thinking...they are very similar...but a pair of Webers in rought shape will run you like $200 bucks or more...and then I've still got to rebuilt them ...but I can find 34-38mm quad carbs for motorcycles all day in good running shape for less than $100 bucks

 

Back in the previous decade we had a running joke going about how many Tillotsons it would take to make a Hemi breathe.
That went on on the Rodder's Roundtable mostly but popped up here on the HAMB too I think.

Problem is using carbs with accelerator pumps or some similar enrichment circuit like on SU's.

SU's would be my choice though, because they are in my opinion the simplest carb around to tune.

 

i put a pair of carbs off a cx500 (silver wing) honda streetbike on a mg midget and it was almost a bolt on. i put a 1/4-20 nut under the needles as a spacer and they ran like buttah.
lately i've been looking at some 40mm mikunis under my bench with thoughts of putting them on a vw trike.

 

I have thought about using 8 Harley CV carbs in a cross ram configuration, but sure would'nt enjoy synching them all up...Would look like a medusa's head hanging on top of the V8 though!

 

There's an article in a '67 HRM by Ak Miller concerning hopping up a Ford 200 six, and he used four carbs from a Honda motorcycle.

 

It could work! You won't know until you try it. I say go for it. I don't know that much about carbs but if you opened the jets a little couldn't you make them work? Make sure you take a ton of pictures and when you get it to work make a tech article about what you went through. Good luck man, keep us updated. JB

 

Well at least I haven't had anybody tell me I've lost my mind....maybe it can be done?

Even if I had to run eight carbs..two banks of 4 on each side..if I could get it to work...it would have ppl staring at it all day long

The other thing I had thought about doing...is I have a 94 LT1 engine that I have thought about using in the 37 Pontiac...but if I got 4 or 8 motorcycle carbs and gutted them (no fuel going in them) so that all then ended up being were a throttle body..and then hide the injectors under them somehow...that would look wicked and should work just like the stock injection...

 

I think I might try something on the bone stock 350 in my 68 C-10..after all right now its got a stock single barrel on it..I know some motorcycle carbs would have to be better than that thing!...

Now to just find the right carbs, make some kind of intake..and get it all to work......this should all be very interesting...

 

It's been done... it's ugly though... and it'll take some real fiddling to make them run right. Jetting, needles... you could make the manifold pretty easy since they usually attach with rubber boots...

 

Have you seen this?? Dont remember where I got the photo, thought it was a crazy set-up

 

I wonder if you could just build a 2 piece adapter type of box that'd bolt to the top of an open bore 4 barrel intake. Fab up the bottom and sides of the box, and then a lid that can be sealed down properly. Open up the bottom of the box to match the open bore of the intake, and drill holes in it to bolt it down to the intake. Mount the carbs (they'd be side mount, right?) to the sides of the box and then fab up your linkage and such. Once it's all setup and situated, you should be able to bolt on a the lid and seal it.

I just had a sick mental image of the linkage and carb mounting idea. Mount on carb on each of 4 sides of the adapter box. Route the linkage to the center of the top of the box and attach it with a 4 point + type of bracket that spins/turns/pivots in the middle, and actuate the throttle cable off of one carb. The middle piece spins and the carbs respond. Would look like a little spider in the middle.

I'd also think that with an adapter similiar to this that the entire setup might be a bit more forgiving if the carbs weren't all syncronized and identical, as they are all independently acting as one central unit - if that makes any kind of sense.

 

This is similar to what I was thinking. If you used 8 of these carbs on a dual quad tunnel ram, it might be kind of interesting - if nothing else. I'd be curious to see how it ran and behaved.

 

I need a few of those SU's with the round SU logo air cleaner. A pair for my next project, and a single one for a future Triumph chopper project.

 

I read in Turning Wheels a Studebaker club mag. A guy put 8 cycle carbs on a carbonfibre log intake manifold he build for a Stude motor . He made air cleaner's, cast to look like old 50's microphone's.

He said it worked well & had the photo's in T.W. I think he worked at The Skunk Works.

 

elcornus,

Unless I'm really missing something...aren't those carbs bolted to the exhaust ports????

 

Reverse flow set-up. Exhaust would come out the top rather than the sides. It effectively gets rid of the intake manifold as a potential bottle neck.

It's a bit complicated to set-up and involves reversing the cam and distibuter but is not that far out.

 

Someone must have ground a reverse rotation camshaft and run the engine backwards. I've got a picture of a flathead in a Bonneville racer in a '52 HRM done up the same way, with a log intake manifold bolted to each side of the block, and eight exhaust stacks sticking out of the intake ports.

 

Been there, done that, got a dirty t-shirt....

GSXR Mikunis on a crossflow headed, 200 Ford inline.

 

mustangsix, so how did it work out?...

I was thinking about running the carbs into a "log" type setup..so that I wouldn't have to worry about tunning them perfectly...that is..if this idea goes anyfurther than me typing about it..

 

Okay...

M/C carbs on car motors have been done - the rate limiting event is the velocity drop when all the throttle slides (or plates) are whacked open. In a heavy (relative to a M/C) vehicle, the motor is gonna nose over, or bog.

To offset this, there are two carb types to pick from. The closest 'old school' type carb would be a Dell 'Orto used on Moto Guzzi V7's, Ambassadors and Eldorados from '67 - '74. What makes this carb work is that it has an integrated accel pump - and it's sized to fill a 350-425 cc cylinder.

the other solution is to run constant velocity (CV) type carbs. These are what's used almost exclusively these days on carbed bikes - they're identificable by a big round diaphragm housing topside. the diaphragm regulates the slide based on vacuum signal - thus keeping the velocity through the carb constant...eliminating the flat spot. There are gajillions of these in M/C yards these days - a 32 - 36MM throat is about the right size for most car apps, BTW.

As for the log manifold - DON'T! For each carb to work properly, it needs to see an individual vacuum signal from the cylinder served. ganging them together will cause a loss of signal when the throttle plates are open - and the engine will die.

6 carbs on a slant six Mopar are the shit - it's still on my 'do' list...

 

Suzuki parts on Plymouth four. Ran 113.75 mph. Bigger nozzles

 

The cam goes the same direction it always did. The lobes are ground so that the intake and exhaust ports are swapped

 

That' s funny that this was brought up, becuase just recently there was a post on the Jockey Journal that got me thinkin about a Weber in place of the two Mikunis on my Bonneville.

 

It won't work on a log. Each carb needs to see it's own intake port.

Mine revved like a banshee, but it was a bitch getting it to idle consistently. Too many moving parts that had to get back to the same place. But it started easily and the throttle response was "right now". No bogs or dead spots. Ran a tad rich, but that was ok.

Oh, and i had to run a pressure regulator to keep the pressure down to 1.5 psi.

 

CV carbs are a tuning nightmare without the factory airbox on them, it would take a dyno and a ton of time to make them streetable with enough for a good sized engine. Most will barely run on the bike with the airbox removed. Anything can be done though with enough work

 

Bingo, I just came back to add that... thanks for beating me to it...

 

Miller ran his m/c carbs on the stock 200 integral log intake with carb flanges brazed to the side of it. Now, I'll have to find the article!