Anyone ever thought about using motorcycle Carburetors?

It's pretty common to run 100+ cubic inch Harleys with a single carb , so I don't see any reason 4 of them wouldn't easily feed most street V8's.

 

friend of mine once built a manifold to put a bank of 4 carburetors off a 750 Honda on a 2000cc Pinto engine in his roadster. Looked cool but those carbs just were never made to flow as much fuel as a 2000cc moor wanted. So he went to Webers. Maybe a really sharp guy would have opened up the passages necessary and made it work.

 

A lot of years ago, we partially sponsered a race car in a four cylinder class. We were using a Ford 2.0 litre (121 CID).

First year we ran 4 Mikuni motorcycle carbs. Engine ran very good, and we won the class. Rules change, no multiple carbs.

Second year we ran a 4 barrel from a '56 Chevy. Engine ran better than with the four carbs, and we won the class. Rules change, any two barrel.

Third year we ran an Autolite 2100 from a Ford 390. Engine ran even better than with the small '56 Chevy 4 barrel and we stomped the class. Rules change, Holley 2 barrel only, of a specified list number.

Thats when we quit.

The motorcycle carbs were not a problem (only 4 of them) but then I have been tuning multiple carb setups for 45 years, so have lots of practice. But you can too, it just takes practice.

Quite honestly, I don't think the end result (other than the knowledge, and the experience gained) will be worth the effort unless you have time to burn, and just want to do it; but IT CAN BE DONE!

Another issue is the "mean time to failure" of the carbs. We expect to get 200,000 or more miles out of any US produced car carb that we restore. Ask some of the bike people how often they rebuild/replace the motorcycle carbs. Our Mikunis were pretty well worn after only a single season.

Bottom line, there will be issues. But if you want the experience, go for it!

Jon.

 

There was an O/T mazda truck in the show scene several years ago that ran four carbs off a gsxr I think and it ran really well. It also looked super clean.

 

During my life I have raced all types of motorcycles from BSA and Triumph short track to motocross and speedway and have a real good understanding of how carberators work. Unless you just enjoy pain I can't think of a good reason to try and get eight single carbs synched and tuned to get a V8 car engine to run right. Just trying to get the cable linkage all adjusted would take hours and the foot pressure required to open the throttles against the return springs in the carb slides would give you a leg like a soccer kicker.

Give me a good manifold and single four barrel any day.

 

Been there done that and even had a T shirt made . These were Tillotsons and probably not the best choice but I wanted to try them(for 35 years i wanted to try this. finally did. I got them to work well with a street grind cam but when I put a big cam in and needed more fuel delivery they are too pressure senstive for my liking. I still have the complete set up though hanging on the wall. I have been told Mikunis are a lot bettter choice. I am currently running a 4 barrel and performace was just as good . I am working on a tunnel ram in the meantime.
Don

 

I had forgotton the issue with the foot pressure. And it is an issue.

Jon.

 

BTTT-
You ever own any of the old Kawi H-2 triples{stock or GAST porting}...weren't worth a damb unless you had them synced and jetted right - but look out if/when you did!...stupid no down 5 up shift pattern! It wasn't rocket science though either...10min to set it and recheck ocassionally for any cable stretch.
Actually the throttle pull wasn't that bad - remember, cyclists used their wrist to hold it....I used to ride 6hrs or better some days and the only thing sore was my back and neck sometimes....unless we hit alot of stop and go traffic and that was clutching effort added in as well- double wammy.

My thoughts, for my 201 flathead 6, would lean towards either the early KZ1300 carbs{not the problematic fuelie set up} or a CBX rack.
Tillys?...I think I still have some from my old Doo TnT 440...

 

Al Cunningham ran 3 S&S carbs on a 320 in. GMC at Bonneville. The one thing I remember is, they could not get the prearsure regulated down enough to keep them from flooding. They eventually put a small fuel resevoir, pumped fuel into the resevoir with a return line back to the fuel tank,they had 3 outlets going to the carbs, this achieved "gravity" flow to simmulate the conditions the carbs were designed for. Al can be reached at Inliners; Texas chapter.

 

Reverse flow and reverse rotation are not the same. You don't have to have one to do the other. I'm sure the SBC pictured runs normal rotation, but reverse flow. You just need the right cam.

 

I'd figure one could dial a fuel reg down far enough to work to make it work...perhaps not....neat idea with the return line though. Kind of odd that an automotive carb needle and seat can handle fuel pump pressure and a motorcycle's carbs can't...smaller floats I guess, less leverage.

 

I've never seen motorcycle carbs on a car engine, but a guy in the office next door to me rides a Goldwing with a Quadrajet on it. That thing runs like someone put after burners on it.

 

you can get spring loaded needle and seats from Sudco I ran a carter electric fuel pump and a low pressure Holley reg set at 2 1/2psi no flooding, some used a return line with a jet in it to adjust pressure

 

I have a Pontiac 230 ci OHC straight 6 that I'll be using in my rod. I've wanted to use MC carbs on it for the cool factor. I see it's been done quite a bit, but what I can't find out it exactly which MC carbs are used in the more successful setups. Anybody have that info?

Thanks!
Chris

 

Most motorcycle carbs are gravity feed, so in order to use them on a car with a fuel pump pressure needs to be very low. Most don't have accelrator pumps either, so it might be tough getting off idle without major stumbling.
There are motorcycles that use carbs with accelerator pumps and also are fed from fuel pumps, so they might work. One of these is the earlier pre fuel injection Honda Goldwing that used a fuel pump and had accelerator pumps in the carbs. Problem is they used 4 carbs on a 1200cc engine, so how many would it take to run even a small V8 or straight 6?