28 replies to this topic

[stevo911_]

Also, what setup were you using (fuel pump, what carbs, what motor setup etc...)?
Just curious about the success rate

Edited by stevo911_, 10 July 2007 - 05:53 PM.

[drag13honda]

good idea on the thread. I’ve been contemplating bike carbs a lot lately, I’ve been doing my homework. I too would definitely like to see the results of this. unfortunately I cannot vote either way, but just saying good idea and thanks.

[stevo911_]

NP, I think a few people around here were wondering
theres an option for you (and myself) now.

[funkmaster]

from all the threads ive read theyre more trouble than theyre worth.
If you want to go fast there are better ways IMO.

[stevo911_]

Thats why I started this thread to get a better idea of the failure/success rate, what setups people were using etc... see if there are common factors, in theory I dont see why they shouldnt work, and I know there have been some people on rpr that have had great success, so this may be the key to finding all the variables (such as using the fuel pump equipped with the carbs vs some random aftermarket one regulated way down)

[zakats]

86 civic DX w/CVCC uber 1337 custom manifold by me! now sitting in my garage tucked neatly in my parts pile
alll stock down to the mech fuel pump

**98(i think) CBR 900RR carbs at the appropriate angle supported by rubber fuel tank filler hose and some temporary bracing

my engine didnt last very long (couple o weeks) with that setup though because I had a weak timing belt and ran it 6 teeth off!
the car pulled harder than ever. butt dyno says I was faster than every SI ive been in.

If I could go back, Id cut the runners and have them welded at a pro shop and fix that timing issue instead of going B series... the ITC's were sweet

final thoughts, I loooved the ITC setup and I'll put em on my crx eventually, one problem with them is that they're too big for the EW's intake runners... they're something like 44mm OD while the EW intake runner is more like 38. thusly I think some 750cc or 600cc bike carbs would be better.... dont quote me on those measurements though BTW i'd need to remeasure. the carbs are perftect size for my B18 though....
-zak

[Kurt]

CAR
1984 civic hatch

ENGINE
Hydra "ew2 block zc pistons zc twin cam head"

EXHAUST
Hand made ss 2'' tube and hand made centre muffler "straight through glass pack " Rear muffler is suzuki GSXR" for street use.

CARBS
1999 Yamaha r1 42mm carbs.

INTAKE MANIFOLD
hand made ss tube .

FUEL PUMP
yamaha r1 electric pump.

This setup works perfect. I think like with any car project you need to do things the correct way from the start, this saves you a lot of trouble in the end. Start with a strong engine that is in good order. Use carbs that other people have had success with and use a set of carbs that used an electric fuel pump in the stock bike they came off. This makes getting fuel to them at the correct pressure a lot easier. Forget about using gravity fed carbs!

If your bike carb setup is running like crap and you have just come back from your local hardware store with a bunch of pvc pipe and knock yourself up a manifold using gravity fed bike carbs, stock honda mechanical fuel pump and jets for a 600cc bike you can hardly expect it to run well if at all.

The way I went about it was first to use bike carbs that I know all the big names in bike carb conversions use and swear by. They are the yamaha r1 carbs. So from the start I know they can be made to work and I was on the right track . I found a set that were in very good condition. The bike had done about 4000km and they looked like new. Nothing worse than trying to get a set of 1972 carbs to work that have been out in the weather for 30 years.

I then made myself a ss manifold that sealed correctly to my cylinder head. Had vacuum ports for brake booster, vacuum advance and 4 carb tuning ports, also the manifold aligned correctly to the carbs spacing. I spent a bit of time getting the throttle linkage smooth and positive. Wired in the electric pump.

Started the car first time and it needed some tuning, bigger jets, and adjustment of needle clip position.

The performance runs rings around the stock efi, and with a fully balanced engine you can pull some strong rpm without a efi rev limiter giving you the ****. Not to mention just how clean and simple the engine bay looks now.

link to video , had to hold cam in one hand and drive with other so kinda crappy. Just throttle response at idle and in a couple of gears.
http://videos.street...968006be38f.htm

[crazi-85crx]

Car:
1985 CRX

Engine:
Hydra (EW2 block, D16A1 head and D16A1 browntop pistons).

Exhaust:
2.25" side-exit with just a cherrybomb... loud.

Carbs:
Honda GS750 32mm carbs.
Putting GSXR 38mm carbs on when new manifold is done.

Intake Manifold:
Chopped stock manifold.
Check this post for my update on making my own manifold.

Fuel Pump:
Something off a Suzuki or Honda motorcycle.

I love my motorcycle carbs. The 32mm's are kinda small for the higher RPM's but they work good after opening the jets up a little.

The basics of it are simple... Get some carbs, make an intake, find a fuel pump, and put it all together. It's the small things, like jetting, that exacerbate the project. I've seen the stock DX fuel pump used with just a pressure regulator, so that's one thing taken care of.

When choosing carbs you don't want to go smaller than 600cc's or 32mm's and be sure to clean them before installing. Fuel injection will be better for some people, it's all about what you know you can do, so read over some projects to see if you're willing to learn what needs to be learned and do what needs to be do'd.

Video of my initial start of it:

[stevo911_]

you havent dyno'd your car or anythign have you crazi?
you've got the exact setup i'm assembling (aside from being undecided on particular carbs)

[crazi-85crx]

you havent dyno'd your car or anythign have you crazi?
you've got the exact setup i'm assembling (aside from being undecided on particular carbs)

I plan to dyno it when the 38's are on and running smoothly.

[stevo911_]

cool, keep me posted
also, your manifold link is a dead end

[RFL85CRXSI]

EW1 block w/ EW3 head
Honda CBR 900RR carbs w/ a partal hacked/fabed manifold

My greatest issue was fuel pressure. When I first put the 900 carbs on and fired it up for the first time, it ran beautifly w/ and extreamly crisp throttle responce. Unfortunetly the reason for the exelent test was due to a massive fuel leak at the "T" conectors in the carburators.
I ran a fuel return before the fuel pressure regulator to solve the issue of too much fuel and burning up my fuel pumps.

[Richard]

bone stock d16a1
chopped stock manifold w/ jb welded injectors holes and water source.
1987 cbr 650rr nighthawk carbs
home depot couplers
carb'd 85 prelude electric fuel pump
odyssey bmx knarps to custom shorten choke and throttle cable

lots o pics in my build thread

ran great on stock settings. drove em for about 3 days till my filterless set up sucked something and wrecked one of the carbs. sold them to phatboycrx and i dont think he could get them to run again after they were rebuilt.

overall view: COOL! sounded awsome, great throttle response, no real change in fuel economy for me

downside: breaks easy?

i stil say go for the sidedrafts at zensport.

[Omega Mugen]

Can you post a picture of the odyssey bmx knarps to custom shorten choke and throttle cable?
Or a link? Anything...

[jay_1gen]

Motor: Brown Top ZC

Carbs: CBR 900RR

This was a pretty exciting build everything runs good I just need to tune everything in.