Bike carbs on cg13de

Thom-micra

Thom-micra

Hi all,

I'm planning on making my cg13 run oldschool on bike carbs.
Why bike carbs and not itb?
well, i just love oldschool, the sound, the smell.
And i think carbs are a little less expensive.

But i have a few questions.
My plan is make some sort of setup like this:
· CG13DE cvt block
· CG13DE crank and rods
· CG10DE pistons
· CG13DE gearbox
· Nismo clutch
· Lightened flywheel
· Fuel pressure regulator
· 4 Carburators
· Catch can
· Custom 4-2-1 exhaust stainless
· Custom full exhaust system
· Polished head
· Sharper cams
· Custom adjustable cam gear

But what carbs can i use best?
And how do i do with the dizzy? Because i want to run without ecu
I think 38mm are to big.
Maybe carburators of a gsxr 600 or something?

Need some tips :)

Thanks

Chears
 
Check out skinners blog, and I_jonez mini micra

If you wanna do away with ecu, you can mod a k10 dizzy to fit.

I used cbr600 carbs with mine, 1.35 jets
 
I used Kawasaki zxr 750 carbs. They have a 36mm which seemed fine. The 40mm ITB's I swapped to are a little bit to big to be honest so I'd imagine 38 might be touching on the large side.

Ignition wise I used megajolt but I've seen people use k10 dizzy's with an adaptor.
 
l_jonez said:
I used Kawasaki zxr 750 carbs. They have a 36mm which seemed fine. The 40mm ITB's I swapped to are a little bit to big to be honest so I'd imagine 38 might be touching on the large side.

Ignition wise I used megajolt but I've seen people use k10 dizzy's with an adaptor.
Click to expand...
and that megajolt is a trigger wheel right?
Thats pure a ignition system?

But a k10 dizzy, can i use that one without ecu?
 
You need the k11 dizzy coupling part that goes to the cam, then stick it on the k10 dizzy

But skinner still uses his k11 ecu to do the spark I yhink
 
Here's pic of mine I made

K10 dizzy, k11 coupler, then I chopped up the k11 dizzy to make a adaptor/spacer

zaqu6yvy.jpg
 
Yep megajolt uses a trigger wheel etc.

Dizzy would need a coil as well

As pork said I think skinner still uses the Nissan ecu for ignition.
 
and what coil needs the dizzy?
Because making a k10 dizzy fit, seems pretty easy.
I can TIG weld the coupler, and mill an adaptor to make it fit

But skinner uses throttle bodies right?
 
1.2 would be better, but you'll want to go to a rolling road and have them change the bobweights and spring stiffnesses to tweak the ignition curve to suit the application
 
edis ford wasted spark setup aint they thom ? and you will probably end up using a throttle position sensor for the load input if you want that quad carb induction roar,
so a lot of grief and a performance compromise tbh :)
 
frank said:
edis ford wasted spark setup aint they thom ? and you will probably end up using a throttle position sensor for the load input if you want that quad carb induction roar,
so a lot of grief and a performance compromise tbh :)
Click to expand...
my english is relatively good, but this is a hard one to understand haha :$
 
Basically, you would need to fit carbs, a throttle position sensor, a crank position sensor sensor and have megajolt mapped, and after all that you would have less power than if you'd just mapped the injection setup.
 
Thom-micra said:
my english is relatively good, but this is a hard one to understand haha :$
Click to expand...
its better than my dutch thom :)
the megajolt uses a crank sensor and a coilpack from an old ford iirc mate, so it sparks at every tdc and btd (top-dead-centre) and wastes half of the sparks.
and i doubt if you will be able to use a MAF or MAP sensor with 4 carbs :)
 
hmm, so not a big power gain from carbs?
thats weird, because my mate has a toyo ae82 with 4A-ge and 2 double dellorthos, but that engine compared to an stock 4age, it is a pretty damn fast car.
and it just has those carbs and other cams
 
Cams mean more air into cylinder so need more fuel. Carbs can supply more fuel. But so can a remap, and injection is much better at metering out fuel so you will get a better afr and more power from a tuned injection setup.
More fuel makes no extra power without extra air, and extra air needs NA tuning. Ading extra fuel without proper tuning is throwing money away.
 
Thom-micra said:
hmm, so not a big power gain from carbs?
thats weird, because my mate has a toyo ae82 with 4A-ge and 2 double dellorthos, but that engine compared to an stock 4age, it is a pretty damn fast car.
and it just has those carbs and other cams
Click to expand...
outright hp @ 7k rpm will be good thom, but the powerband/daily drivability will be compromised tho, and 20L/100km too!
 
Well, with the setup above, what hp do i need to look at +-?
And its not just because i want high power or so, because then i would choose itb with mappable ecu etc etc.
But this is my first engine "build" so i want to take some experience with me. Just have some fun building it, and learn things about the engine for "beginners" :)
 
Thom-micra said:
Well, with the setup above, what hp do i need to look at +-?
And its not just because i want high power or so, because then i would choose itb with mappable ecu etc etc.
But this is my first engine "build" so i want to take some experience with me. Just have some fun building it, and learn things about the engine for "beginners" :)
Click to expand...
your main + will be the noise eh thom :)
fitting bike carbs to a k10 is easy, because you have the correct fuel pressure and the stock ignition system (and loads of room) , but fitting them to a CG13 is a lot of work tho
i managed to squeeze 109hp N/A with some ghetto mods, and the 1/4 miles times were close to what the current +t engine does, but i had to rev the nuts off it all the time tho
 
I ran carbs and megajolt with a map sensor ( need a feed from each carb all tee'd together ) no problem.
I've since moved to ITB's mainly for the ease of tuning.
 
frank said:
your main + will be the noise eh thom :)
fitting bike carbs to a k10 is easy, because you have the correct fuel pressure and the stock ignition system (and loads of room) , but fitting them to a CG13 is a lot of work tho
i managed to squeeze 109hp N/A with some ghetto mods, and the 1/4 miles times were close to what the current +t engine does, but i had to rev the nuts off it all the time tho
Click to expand...
and what type of mods did u do?
Its not just that i want to put carbs on a cg13, but i want to do it as good as possible.
 
Enuo said:
With all your mods, carbs might give +5/10hp on top of a stock mapped injection system?
Click to expand...
wait, 5/10hp more as mapped injection.
but how much hp would u gain by mapping injection?
when i first saw your comment i was like, only 5 to 10hp more as stock engine?? :D
 
No, 5-10 more with carbs than an untuned ecu (just a guess), and maybe 8-13 more than untuned ecu with tuned ecu, bit as frank said, daily driving will be WAY better with injection
 
Carb setups on here have shown good mpg but as an around town it would become a bit tiresome. You need the revs to pull the vacumm slides open so ur going to be sluggish around town. Lightly modified mine needed to be over 4k rpm to get some life into her
 
Mine was fine in town etc and would pull from 2k but that was on standard cams.
I was getting around 45mpg but that was in a mini ( cg13 engine )
 
Well, i'm still going to build it, want to get as much out it as i can.
I'm only thinking of the carburators right now.
I already decided to use trigger wheel and megajolt for ignition.

But the carbs, I have 2 options, flatslides, like Keihin FCR or Mikuni RS
Or i can use just regular bike carbs with continuous vacuum.
I personally really like high throttle response, and CV carbs dont have that.
It takes slight longer to create open up fully because of the vacuum, while something like FCR is just much directer
 
Mine where CV and I had no problems with throttle response and CV carbs provide better mpg apparently.

Which ever way you go you won't be disappointed.
 
true, but length of intake has to do with torque at low or high rpm
but Flatslide carbs are faster response then cv, because cv needs to create that vacuum. its not seconds, but side to side, it has some difference.
 
Thom-micra said:
true, but length of intake has to do with torque at low or high rpm
but Flatslide carbs are faster response then cv, because cv needs to create that vacuum. its not seconds, but side to side, it has some difference.
Click to expand...
flatsides have no acceleration enrichment tho thom, the c/v carbs do, which means that flatsides need to run inherently very rich
 
My nismo clutch came yesterday, its for a 1.3
but is it true that the gearbox from a first facelift 1.0 fit on a 1.3?
and if it is possible, would my nismo clutch fit?
 

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