Craigorypeck
|
| posted on 13/9/10 at 07:54 PM |
|
|
Carbs have arrived, some info please
Hi. My '98 ZX9R carbs arrived today, I have some silly questions that have been covered before I presume.
As these are going on a complete freshly built engine I need them to fire up straight away so the cam doesn't get screwed up, will 180 main jets
be ok? What about idles? And whats the deal with the needle??
Few pics maybe someone can help me with.
NA cosworth BTW
|
|
|
|
|
mistergrumpy
|
| posted on 13/9/10 at 08:01 PM |
|
|
A = ?
B = Air jet thing that gets blocked when using BEC.
C = Coolant for carbs to stop them freezing. Just remove or ignore this. It normally feeds off the water pump on the bike but as you're not BEC
you won't have to block anything. No one uses it.
D = Mixture screw. Screw in to lean the mixture.
E = Air breather. Do NOT block this off. I learned the hard way. The engine will not work right if you do. Put a filter on if you like. I've yet
to do this though.
F = Fuel feed to carbs.
[Edited on 13/9/10 by mistergrumpy]
[Edited on 13/9/10 by mistergrumpy]
|
|
|
jacko
|
| posted on 13/9/10 at 08:07 PM |
|
|
180 may/will be 2 big
b= air corrector hole may need blocking will need rolling road to find out
D = air screw
E= air breather fit a small air filter to it
F== fuel in
Dont know what C is need a better photo could be water if so block off
|
|
|
cosmick
|
| posted on 13/9/10 at 08:40 PM |
|
|
A Pilot Air Jet
B Main Air Jet also known as Air Corrector Jet
C Carb Heater system (not Required unless you run in cold weather)
D Pilot Mixture Screw
E Float Chamber Breather (Must breath atmospheric air pressure at all times)
F Fuel Line In
NB The Float Chamber pipes can be connected to a pipe and tucked away somewhere where the pipe will not be pressurised ie, do not face it forwards or
backwards in a pressurised area as this will drastically affect mixture either by blowing air into the float chamber (flooding) or Sucking air out
(starving).
If it can't be fixed with a hammer then its probably an electrical problem.
|
|
|
Craigorypeck
|
| posted on 13/9/10 at 09:24 PM |
|
|
I'm used to seting up dcoe/dhla so i'm slightly familiar, so the pilot air jet is like the hole on top of the emulsion tube of the idle
circuit, is there an idle jet in these carbs?
The main air corrector jet effects the mixture of the main jet like in webers
Pilot mixture screw is like the idle mixture screw
And the main jet is in the bottom of the carbs in the float bowl.
The needle has a ribbed top with a washer on it, what exactly does this do and what effect does moving the washer have
Thanks everyone
|
|
|
mistergrumpy
|
| posted on 13/9/10 at 09:36 PM |
|
|
I believe altering the needle height (moving the washer along the ribbed part, which incidentally must be a Dynojet one as standard ones aren't
ribbed) affects the mid range fuelling.
Altering the main jet alters the idle fuelling.
|
|
|
cosmick
|
| posted on 13/9/10 at 09:50 PM |
|
|
The main difference between these carbs and Webers is that these carbs are CV type ie Constant Velocity. they rely upon the continuous flow of air to
keep the slide up. So, if the air/fuel ratio goes out, the slides will fall or flutter/dance up and down. The needle has adjustment to richen or lean
the mid range. Usually, the needle will be found in the middle notch so that this can be moved either way to lean or richen mixture. THE BIG PROBLEM
with kit cars and CV carbs is the lack of air filter ie, filters that have little or no restriction. CV carbs rely upon depression to raise the slide.
So a lot of them have the air corrector blocked when using such filters as Pipercross or K&N.
When you have fitted the carbs, if the slides flutter when opening the throttle try closing off the main air jet with some blue tack or similar. if it
improves the throttle response, then you are going in the right direction. Lifting the needle to the bottom notch will richen the mid range and help
as well.
If it can't be fixed with a hammer then its probably an electrical problem.
|
|
|
Craigorypeck
|
| posted on 13/9/10 at 11:25 PM |
|
|
I see... I think I'm getting the drift now.
The main jet is top end and the pilot circuit is idle just as in webers and everything in between is regulated by the needle, so by moving the needle
up or down on it's washer you effectively have a pump jet effect too?
I have noticed that the floats are plastic and are not adjustable so mounting them properly is very important to make sure fuel height is correct, is
30 degrees correct for ninjas?
I was going to make a back plate and adapt a pair of regular K&N pancake filters from a pair of weber 40s to fit on them.
Thanks again
|
|
|
Craigorypeck
|
| posted on 14/9/10 at 09:57 AM |
|
|
is there anything missing from the float bowl? Those holes look like something should be in them ???
Dont reply with "petrol" LOL
|
|
|
mistergrumpy
|
| posted on 14/9/10 at 10:30 AM |
|
|
Nope it all looks to be there.
Not to be dismissive at all but if you look on kawasaki.com,
select owner info -
parts diagrams -
motorcycle -
select 1998, "ninja zx9r"
parts diagrams -
zx900c1
then choose carburettor or carburettor parts. Whatever you need to know.
Keep asking though if you've any troubles theres a few with ZX9's here and mor using the carbs on car engines so you should get your
answer.
|
|
|
Craigorypeck
|
| posted on 14/9/10 at 03:53 PM |
|
|
Thanks! Will do!
|
|
|
jacko
|
| posted on 14/9/10 at 05:21 PM |
|
|
yep just ask 
|
|
|
Craigorypeck
|
| posted on 14/9/10 at 07:58 PM |
|
|
How many turns out from fully seated should the idle mixture screw be as a rough guide for first start up?
carbs are now completely striped and cleaned in thinners, they look brand new.
[Edited on 14/9/10 by Craigorypeck]
|
|
|
jacko
|
| posted on 14/9/10 at 08:52 PM |
|
|
At a guess 1 - 1.5 turns out mine are 1 but my carbs a E's what are yours ? b's or c's ?
|
|
|
DRC INDY 7
|
| posted on 14/9/10 at 09:08 PM |
|
|
mine are zx6r carbs an turned out 4 turns which gives me 3.5%co stoic main jets 1.7mm and pulls strong to my 7000rpm limit
https://www.facebook.com/groups/462610273778799/
Puddle Dodgers Club
|
|
|
Craigorypeck
|
| posted on 14/9/10 at 09:22 PM |
|
|
My carbs are C1s. 98's
I take it a turn is a full 360 as sometimes peeps say a turn is 180..
What size engines are you chaps running???
[Edited on 14/9/10 by Craigorypeck]
|
|
|
