QUAD Motorcycle Carbs

[Zufer]

so a little update... two of the carbs weren't working right and the vacuum control pistons weren't opening all the way. So i got that fixed and can now say that i like these carbs a lot better than the weber. There is equal if not more power. Definitely some more torque through the mid range. And power delivery is very smooth. It also drives more like and efi car where you can just mash the gas and it doesn't hesitate or anything. So now i just need to figure out an air filter and do a little clean up on the manifold and the project will be done.

Ok for anyone thinking of doin this..... make sure you realize the extent of what you are doin.... It took me a good couple weeks of working on it fairly regularly to get the car to start on its own and actually be drivable. This is not a mod for the amatuer mechanic or someone who has never tuned a carburetor before. However for those who feel they can undertake it i think it is very worth while. But a time slip and a dyno this summer will show me how worth while.

[bobafett]

you need a baseline with your weber now though.

[Zufer]

didn't someone baseline an accord quite a while ago stock... and see like 85 whp's. But you are right a comparison between a weber and these would be cool... Maybe if i feel really motivated this summer! And rich!!!! that takes a bit of dyno time to compare both

[lostforawhile]

so a little update... two of the carbs weren't working right and the vacuum control pistons weren't opening all the way. So i got that fixed and can now say that i like these carbs a lot better than the weber. There is equal if not more power. Definitely some more torque through the mid range. And power delivery is very smooth. It also drives more like and efi car where you can just mash the gas and it doesn't hesitate or anything. So now i just need to figure out an air filter and do a little clean up on the manifold and the project will be done.
Ok for anyone thinking of doin this..... make sure you realize the extent of what you are doin.... It took me a good couple weeks of working on it fairly regularly to get the car to start on its own and actually be drivable. This is not a mod for the amatuer mechanic or someone who has never tuned a carburetor before. However for those who feel they can undertake it i think it is very worth while. But a time slip and a dyno this summer will show me how worth while.

are your carbs slide carbs or based on the variable venturi(su) design? a lot of the japanese bike manufacturers abondoned the old slide carb design for the su design carb on bikes. they offer much better mixture control and better driveability at low rpms. the two designs look the same,but on a slide carb the throttle directly controls the piston,but on the variable venturi design the piston is controlled by airflow through the throttle bore and the throtle has no direct connection to it. how it works is that the top of the piston has a passage to vacccume in the throttle bore,when the throtle plates open,this vaccume causes a low pressure area above the piston,causing it to rise,this exposes the metering needle and allows more fuel to enter the throttle bore. when the vaccume stabilizes the piston comes back down lowering the needle and allowing less fuel to enter the bore. it's very simple and is very accurate. the SU carbs were the original carb to do this,and the design was copied many times over the years. a lot of these copies were on bikes. primarily because it worked so well and it was extremly simple.

[Zufer]

yes they are the variable venturi type. What part of my comment was that a response to?

[lostforawhile]

yes they are the variable venturi type. What part of my comment was that a response to?

oh you said they hadn't been working right,I was just wondering what kind of carbs you had been using,I am doing a project sort of like this right now also,it's interesting to compare the different carb projects going on. who needs fuel injection? LOL.

[MessyHonda]

who needs fuel injection? LOL.

i do...but is still got carb love as long as it runs right

[teck]

sexy!. you pulled those off an older model CBR didnt you?? my friend has an 80s CBR and the cards are exactly the same

[Zufer]

I believe they are off a 1986 shadow, but i got them from a guy on ebay so i don't know for sure

[teck]

ahh

[Zufer]

Enjoy, comments are welcome.

[MessyHonda]

very nice.

[wprocomp]

your cars about to ambushed by the grass lol

[87lxiaccord]

Does it run? Where'd you get that strut bar?

[russiankid]

Are you running the stock fuel pump to handle those? Anyways vids!!

[snoopyloopy]

hothothot. that's pure sex right there. how does it run? any power numbers, or at least estimates?

[Zufer]

it runs, still needs a little bit of tuning, but runs amazing, yep stock fuel pump. As far as power, well it was noticably better than a really well tuned weber 32/36. And it is extremely smooth power.
and the strut bar is a shucks civic bar that i redrilled the holes on and flattened out the bends in the bar

[Legend_master]

That is awsome dude, and I bet tuning 4 different carbs is a bitch .

[A18A]

thats sexy

[che3wy]

wow nice. i say for future reference turn down the white balance there's a bit of overexposer making the picture washed out. sorry a bit of my photography kicking in. love the carbs man

[HondaBoy]

looks pretty cool. would it be possible for you to make some sort of video? i'd love to see a vid under the hood and then while driving.

[guaynabo89]

good work looks really nice.

I have one question though.... Why not leave them individual and run some trumpets with foam filters on them instead of tying it into that plenum? Did you make tha too?

[russiankid]

good work looks really nice.
I have one question though.... Why not leave them individual and run some trumpets with foam filters on them instead of tying it into that plenum? Did you make tha too?

I was thinking the same thing at first, but couldn't word it correctly.

[skycam_313]

NICE.

[LX-incredible]

Cool.