dmrider_10
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| posted on 7/8/14 at 12:32 PM |
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Running Lean at WOT with Kawasaki ZX6R carbs???
My car has a Ford I4 RS2000 engine, 2.0L running on Kawasaki ZX6R carbs with megajolt ignition. It has a Innovate LC1 wideband fitted along with a AFR
gauge.
Last night i noticed at WOT the gauge swinging around to around 16.5:1 which is obviously too lean. On further investigation today it seems to swing
that way past half throttle ish. It didn't do this previously, it would maintain 14:1 ish to redline.
Ive had LC1's on other cars in the past and would say it probably needs a re calibration in free air, except the gauge reads
"correct" or to put it better, what you would EXPECT it to read at all other times, cruise, around town etc so Id say its reading
accurately.
Now I know nothing about carbs if Im honest (give me a laptop!) but was wondering what should be me first steps and is there anything to obviously
check first? This could be the ideal time to get more familiar with them.
Thanks
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mcerd1
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| posted on 7/8/14 at 12:43 PM |
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if it was running well before with all the jets etc. set correctly and you've not changed anything then I guess something has got stuck / needs
a clean...
has it sat for any length of time with old fuel in it ?
see here for some background on this style of carb:
http://www.gadgetjq.com/keihin_carb.htm
[Edited on 7/8/2014 by mcerd1]
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dmrider_10
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| posted on 7/8/14 at 01:04 PM |
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Thats for the response/link
Well that was my best guess, something is blocked. Any advice on how deep i need to go in removing the carbs/stripping them to get to the jets etc?
Thanks
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davidimurray
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| posted on 7/8/14 at 01:24 PM |
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I've got these on my car and have done lots of setting up with them - they are great and really easy to setup.
First thing is get everything clean - blowing through is not enough! Drain the float bowls and remove them. Looking at the bottom you will see two
brass jets near the middle.One is screwed into a hex adaptor - that is the main, just to the side of that is another jet - that is the pilots. Take
both of these jets out and soak in a glass of carb cleaner for 24hours. Blowing through won't do it - I tried numerous times and even when
'clean' an enormous amount of crap came out when soaked.
When it's back together see how it goes. I found balancing the carbs was very important - my Pinto is quite sensitive to how well they are
balanced.
Gallery 1 http://www.facebook.com/media/set/?set=a.116893465324.130778.601005324
Gallery 2 http://www.facebook.com/media/set/?set=a.245243755324.181913.601005324&l=a9831a9319
Gallery 3 http://www.facebook.com/media/set/?set=a.440671625324.232627.601005324&l=3f0d42c523
Gallery 4 http://www.facebook.com/media/set/?set=a.490098255324.297598.601005324&l=efb083b7df
Gallery 5 http://www.facebook.com/media/set/?set=a.10150244028550325.366987.601005324&l=583fd5cd3a
Gallery 6 http://www.facebook.com/media/set/?set=a.10150550640070325.430417.601005324&type=3&l=fe779b358c
Duratec Engine Swap https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f " target="_blank"> https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f
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dmrider_10
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| posted on 7/8/14 at 01:29 PM |
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Just what I was hoping, someone else with these carbs chipping in!
So you do this whilst they are still on the car? Or remove them from the block?
Thanks
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davidimurray
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| posted on 7/8/14 at 01:38 PM |
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No worries - I struggled for ages to get my carbs right but was a great learning experience - wouldn't call myself an expert but have learnt a
lot about setting them up!
On my car, I can do everything with them on - i.e. remove all the jets, balance carbs and adjust the needles. Mine are close to the edge of the body,
but there is lots of room below, so I put a mirror down and just check the screwdriver is in the jets properly. Be warned the float bowl screws are
made of soft cheese, so if you have never had them off before you may want to do them on a bench and replace with some capheads - then they are easy
to get from below.
How much setup have you done with your carbs?
Gallery 1 http://www.facebook.com/media/set/?set=a.116893465324.130778.601005324
Gallery 2 http://www.facebook.com/media/set/?set=a.245243755324.181913.601005324&l=a9831a9319
Gallery 3 http://www.facebook.com/media/set/?set=a.440671625324.232627.601005324&l=3f0d42c523
Gallery 4 http://www.facebook.com/media/set/?set=a.490098255324.297598.601005324&l=efb083b7df
Gallery 5 http://www.facebook.com/media/set/?set=a.10150244028550325.366987.601005324&l=583fd5cd3a
Gallery 6 http://www.facebook.com/media/set/?set=a.10150550640070325.430417.601005324&type=3&l=fe779b358c
Duratec Engine Swap https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f " target="_blank"> https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f
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dmrider_10
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| posted on 7/8/14 at 01:47 PM |
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Luckily I have a spare set of zx6 carbs right here for reference which is good. I assume the bowl is just the black outside cap thing?
I've done zero carb setting up/tuning. I bought the car a month ago and it was running well and AFRs were good.
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davidimurray
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| posted on 7/8/14 at 01:53 PM |
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The bowl is the aluminium cover on the bottom. This will be full of fuel so use the little 'nipple' on the bottom to drain them.
See this for view of the bottom -
[Edited on 7/8/14 by davidimurray]
Gallery 1 http://www.facebook.com/media/set/?set=a.116893465324.130778.601005324
Gallery 2 http://www.facebook.com/media/set/?set=a.245243755324.181913.601005324&l=a9831a9319
Gallery 3 http://www.facebook.com/media/set/?set=a.440671625324.232627.601005324&l=3f0d42c523
Gallery 4 http://www.facebook.com/media/set/?set=a.490098255324.297598.601005324&l=efb083b7df
Gallery 5 http://www.facebook.com/media/set/?set=a.10150244028550325.366987.601005324&l=583fd5cd3a
Gallery 6 http://www.facebook.com/media/set/?set=a.10150550640070325.430417.601005324&type=3&l=fe779b358c
Duratec Engine Swap https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f " target="_blank"> https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f
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mcerd1
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| posted on 7/8/14 at 04:11 PM |
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quote:
Originally posted by dmrider_10
I assume the bowl is just the black outside cap thing?
cap on top has the diaphragm inside - this is the bit that causes the slide be drawn up against the spring due to the pressure difference
here's a very simplified diagram of the Keihin CVK carb:
(it doesn't show the float - that would be shown just below the jets)
and here's the parts diagram for the ZX6R carb (I picked a 1995 model)
http://www.cornwallkawasaki.co.uk/shop/shop.php?cmd=showdiagram&id=2057
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dmrider_10
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| posted on 8/8/14 at 10:48 AM |
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Just to confirm, when removing the jets, the central one with the hex head holder, I'm only removing the flat he's screw part and leaving
the hex holder in situ?
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davidimurray
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| posted on 8/8/14 at 01:48 PM |
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You only need to take the jet out, i.e the one with the screwdriver slot
Gallery 1 http://www.facebook.com/media/set/?set=a.116893465324.130778.601005324
Gallery 2 http://www.facebook.com/media/set/?set=a.245243755324.181913.601005324&l=a9831a9319
Gallery 3 http://www.facebook.com/media/set/?set=a.440671625324.232627.601005324&l=3f0d42c523
Gallery 4 http://www.facebook.com/media/set/?set=a.490098255324.297598.601005324&l=efb083b7df
Gallery 5 http://www.facebook.com/media/set/?set=a.10150244028550325.366987.601005324&l=583fd5cd3a
Gallery 6 http://www.facebook.com/media/set/?set=a.10150550640070325.430417.601005324&type=3&l=fe779b358c
Duratec Engine Swap https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f " target="_blank"> https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f
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dmrider_10
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 posted on 11/8/14 at 11:54 PM |
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Ok just to keep this up to date, I let the jets soak in carb cleaner for 48 hours, blew them out and refitted along with the cleaned out bowls etc.
Its now running like a pig :-(
Most of the time its idling at around 17/18:1 and is now more erratic during normal driving, generally leaner than it should be everywhere.
Does the choke on these carbs just add more fuel/richen the mixture? I tried to counteract the lean-ness by using the choke, the AFR gauge reacts and
swings rich only to then go back to lean (with the choke left in the same position)?!
Ill investigate more tomorrow.
Thanks
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whitestu
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| posted on 12/8/14 at 08:42 AM |
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Have you checked for air leaks on the inlet?
What manifold are you using?
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dmrider_10
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| posted on 12/8/14 at 08:49 AM |
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Pretty sure it's homemade by the previous owner. The fact that I couldn't balance it with the choke said to me air leak actually
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dmrider_10
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| posted on 12/8/14 at 03:57 PM |
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Well took the carbs off and at first I when I saw this i thought id cracked it!
But its not all the way through, will replace it anyways though.
Looking at this image, should these two ports be connected together at all?
Also decided to check the plugs to see if they told a story at all, interestingly 1 and 4 (fed from same coil) looked like this:
And 2 and 3 (the other coil) looked slightly but noticeably whiter:
This is the home made mani:
[Edited on 12/8/14 by dmrider_10]
[Edited on 12/8/14 by dmrider_10]
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mcerd1
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| posted on 12/8/14 at 11:41 PM |
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make sure you use fuel resistant hoses to attach the carbs
check the diameter but these should be what your need:
Silicone Hose 40mm Fluro Lined Bike Carb Kit BLACK
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whitestu
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| posted on 13/8/14 at 07:35 AM |
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The pipes are part of a heater circuit used on the bike and aren't generally used on cars so no need to worry about them.
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FASTdan
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| posted on 13/8/14 at 09:09 AM |
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My bet is an air leak developed over time. Incidentally even your original 14:1 is lean for loaded conditions - should be aiming for low-mid 13
AFR's.
Those hose clamps don't look ideal and as said make sure the silicone hose is fluoro lined fuel resistant otherwise they will break down.
[Edited on 13/8/14 by FASTdan]
NEW danST WEBSITE NOW LIVE! Bike carbs, throttle bodies and more......
http://www.danstengineering.co.uk/
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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dmrider_10
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| posted on 13/8/14 at 11:02 AM |
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Yeah Ive got some new flouro hoses on order and clamps although I think those existing clamps are better than they appear really.
Im just hoping on reassembly, balancing and adjusting that everything is normal.
Another possibility is the fuel filter? Probably worth changing that too.
[Edited on 13/8/14 by dmrider_10]
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dmrider_10
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| posted on 14/8/14 at 05:36 PM |
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Just got a carbtune pro of a mate in work to balance the carbs.
Am I going to be able to use these as I dont recall any vac ports to plug them up to?
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19sac65
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| posted on 14/8/14 at 05:45 PM |
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Not if youve no vac pipes
Best use one designed for webers etc that check vac at carb mouth
Set mine up fine with one
If you think theyre miles out you can check 99% with mig wire under each butterfly as a feeler gauge
Adjust master carb ( with the throttle cable attached to ) by the idle cable,then set others to match
Start and reset idle and tps
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mcerd1
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| posted on 15/8/14 at 07:35 AM |
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quote:
Originally posted by dmrider_10
Just got a carbtune pro of a mate in work to balance the carbs.
Am I going to be able to use these as I dont recall any vac ports to plug them up to?
if you want to use it you'll need to weld the ports into your manifold
this is the type you can use without vac lines:
http://www.ebay.co.uk/itm/like/271152160983?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&device=c&adtype=pla
&crdt=0&ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=108&ff19=0
shop around there are plenty of places selling them 
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dmrider_10
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| posted on 16/8/14 at 07:24 PM |
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Ok so for the second time Ive had the carbs in bits, and rebuilt them up. I found one of the idle adjustment screws was missing a O ring and a washer,
and another just missing the washer. Luckily having a spare set of these carbs I've now replaced them.
Ive also got new fluoro lined silicone joiners to the manifold and clamps.
I cleaned everything, blew everything out, inspected the diaphragms, jets etc and re assembled.
Has it resolved anything? No :-(
I set the idle screws each to 3 turns out. Ill be honest, I haven't balanced the carbs, but nor have I touched the screws since the car worked
properly so that doesn't really concern me.
AFRs are still all over the place :-(
Seems to be running around 14:1 for normal driving but its very random at higher revs/load.
Im really fed up with it now its doing my head in!
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deezee
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| posted on 17/8/14 at 09:07 AM |
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Sorry to hear your having trouble with the car. The engine was tuned from WOT backwards to cruise. So the needle positions and jet sizes where
chosen to give a 12.5-13 on WOT. Then tweaked for cruise. The ignition timing from the Megajolt can affect the mixture, so it would be worth
plugging a laptop into it and making sure its reading all the engine sensors correctly. As if it can't read sensors it can't progress
through the table. Adjusting the carb needle positions by just one notch will richen/lean up the mixture considerably. All this should be done with
the air filter on, as removing the filter leans up the engine lots.
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davidimurray
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| posted on 19/8/14 at 03:15 PM |
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quote:
Originally posted by dmrider_10
Ok so for the second time Ive had the carbs in bits, and rebuilt them up. I found one of the idle adjustment screws was missing a O ring and a washer,
and another just missing the washer. Luckily having a spare set of these carbs I've now replaced them.
Ive also got new fluoro lined silicone joiners to the manifold and clamps.
I cleaned everything, blew everything out, inspected the diaphragms, jets etc and re assembled.
Has it resolved anything? No :-(
I set the idle screws each to 3 turns out. Ill be honest, I haven't balanced the carbs, but nor have I touched the screws since the car worked
properly so that doesn't really concern me.
AFRs are still all over the place :-(
Seems to be running around 14:1 for normal driving but its very random at higher revs/load.
Im really fed up with it now its doing my head in!
Have a go at balancing them. The AFR you are reading is the average of all cylinders so you could have one lean and the rest rich. Also check for any
exhaust leaks that could be screwing with the Lambda. Any sign of any misfires?
It is worth going through checking the settings/balance and even floats systematically as they can all contribute.
Are you seeing lean at WOT? Any fuel filters that could be blocked? I had this problem and put some flowrates for my ZX6r pump on here in a post about
misfires.
Cheers
Dave
[Edited on 19/8/14 by davidimurray]
Gallery 1 http://www.facebook.com/media/set/?set=a.116893465324.130778.601005324
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Gallery 4 http://www.facebook.com/media/set/?set=a.490098255324.297598.601005324&l=efb083b7df
Gallery 5 http://www.facebook.com/media/set/?set=a.10150244028550325.366987.601005324&l=583fd5cd3a
Gallery 6 http://www.facebook.com/media/set/?set=a.10150550640070325.430417.601005324&type=3&l=fe779b358c
Duratec Engine Swap https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f " target="_blank"> https://www.facebook.com/media/set/?set=a.10152527759580325.1073741828.601005324&type=1&l=40aae5e72f
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