The Keihin PWK28 Carb. Thread
Moderator: rztom
The Keihin PWK28 Carb. Thread
Making this thread as a data reference for those who want a stock carb replacement
that is affordable, has a large modern supply line and is easy to tune and care for.
After going through multiple different Mikuni/Keihin/Oko etc. options, decided on the Keihin PWK28.
For the unfamiliar, it is the modern version of the carb that came on the Kawasaki KR1.
Supply: One of the strong points of the carb. is that it is the current,
and has been for over a decade, carb. for the Kawasaki KX85/KX100 and Yamaha YZ85.
Modern supply, modern parts, easy accessibility and will be stocked till we're all fertilizer.
When calling to order 4 and asking if they had enough.....they laughed at that.
Cost: Because factory Kawi has boatloads of them, they can be had for an extremely affordable price.
You may notice some real Keihins (not OKOs) are listed on sites for $200-$300 each, like for the YZ85 etc.
But it was noticed that Kawasaki was selling the KX85 PWK28's for ~$86.
http://www.kawasakipartsnation.com/
I thought these were the cheap OKO knockoffs that many have had issues with, that are commonly about $80.
So I ordered 4 to see what was up and they just came in.
The $86 Kawasaki ones are real, made in Japan, factory Keihin PWK28's with the green factory
inspected markings, the nice castings, nice polished slides, good jetting
and even come with fresh Keihin vent tubes and clips....very nice.
Tuning data: Jetting specs and tuning results will be posted as the bike is set up.
Baseline will be what the KX85 comes stock with ie. 45/#3 NAPE/140 which should be close. (Keihin jetting is different than Mikuni's)
Based on what people run on the KR1(125)/KX100, it will prob be around 42/#2 NAPF/135 but we'll see.
A carb is going off to Bill Wilson so that he has accurate cable lengths for his throttle conversion for people in the future.
The carbs can either be run with pods, as they are not as sensitive to signal as the stockers,
or with FZR400 rubber airbox connectors on the ears-bells with pods or the stock airbox.
The intake boot side is the stock 35mm size on the PWK28.
Sudco has Keihin plunger cable kits if people want to retain the stock remote choke setup.
To get stock like throttle pull, they'll have FAST racing light springs in the slides. We'll see if they have to be cut.
I'm going to try to get the bike dialed with both the NAPE (KX85) and NAPF (leaner KX100) needles.
This way, high altitude/warmer peeps can order KX100 PWK's and low altitude/cooler peeps can get KX85 PWK's.
$86 either way and the jetting won't even need to be changed.
As the bike gets put together and dialed in a couple weeks, I'll post the tuning data.
that is affordable, has a large modern supply line and is easy to tune and care for.
After going through multiple different Mikuni/Keihin/Oko etc. options, decided on the Keihin PWK28.
For the unfamiliar, it is the modern version of the carb that came on the Kawasaki KR1.
Supply: One of the strong points of the carb. is that it is the current,
and has been for over a decade, carb. for the Kawasaki KX85/KX100 and Yamaha YZ85.
Modern supply, modern parts, easy accessibility and will be stocked till we're all fertilizer.
When calling to order 4 and asking if they had enough.....they laughed at that.
Cost: Because factory Kawi has boatloads of them, they can be had for an extremely affordable price.
You may notice some real Keihins (not OKOs) are listed on sites for $200-$300 each, like for the YZ85 etc.
But it was noticed that Kawasaki was selling the KX85 PWK28's for ~$86.
http://www.kawasakipartsnation.com/
I thought these were the cheap OKO knockoffs that many have had issues with, that are commonly about $80.
So I ordered 4 to see what was up and they just came in.
The $86 Kawasaki ones are real, made in Japan, factory Keihin PWK28's with the green factory
inspected markings, the nice castings, nice polished slides, good jetting
and even come with fresh Keihin vent tubes and clips....very nice.
Tuning data: Jetting specs and tuning results will be posted as the bike is set up.
Baseline will be what the KX85 comes stock with ie. 45/#3 NAPE/140 which should be close. (Keihin jetting is different than Mikuni's)
Based on what people run on the KR1(125)/KX100, it will prob be around 42/#2 NAPF/135 but we'll see.
A carb is going off to Bill Wilson so that he has accurate cable lengths for his throttle conversion for people in the future.
The carbs can either be run with pods, as they are not as sensitive to signal as the stockers,
or with FZR400 rubber airbox connectors on the ears-bells with pods or the stock airbox.
The intake boot side is the stock 35mm size on the PWK28.
Sudco has Keihin plunger cable kits if people want to retain the stock remote choke setup.
To get stock like throttle pull, they'll have FAST racing light springs in the slides. We'll see if they have to be cut.
I'm going to try to get the bike dialed with both the NAPE (KX85) and NAPF (leaner KX100) needles.
This way, high altitude/warmer peeps can order KX100 PWK's and low altitude/cooler peeps can get KX85 PWK's.
$86 either way and the jetting won't even need to be changed.
As the bike gets put together and dialed in a couple weeks, I'll post the tuning data.
Andrew
-
- Posts: 348
- Joined: Thu Nov 17, 2005 3:35 pm
- Location: Salisbury
Honda also used them on the latest CR85, but they charge far more than Kawasaki does. Just another option in case anyone is looking for second hand. In Canada you can get jets, needles and other parts from http://www.winnerscirclecanada.com/index.php
- aaronmvrider
- Posts: 1401
- Joined: Fri Nov 21, 2008 7:43 pm
- Location: Central Coast New South Wales
wolfgangh wrote:What are FAST racing light springs? I am using 4 PWK28s in my ANTENA3 bike, and throttle operation is really strong with stock PWK springs. I need to find lighter ones - what would you use?To get stock like throttle pull, they'll have FAST racing light springs in the slides.
he would use fast racing light springs....
i am guessing they are the same length with less resistance
are you referring to the heaviness of throttle operation ???
my rides
rz 500 1984
2 x rz 350 1984
mv agusta f4 1000 2004
rz 500 1984
2 x rz 350 1984
mv agusta f4 1000 2004
Wolfgang, there are basically 5 things you can do.
- run these springs http://www.farmandsandtoys.com/partdeta ... partid=119
- further cut those springs, need testing to make sure slide+spring are heavy enough to prevent runaway throttle
- use a cable luber to fill the cables with a very low viscosity lube
- install a roller bearing throttle tube or bar end roller bearing
.......haven't done the legwork to figure which one works for us if at all
- reroute/recut your tight bend cable portions
- didn't include a slower ratio throttle since ours is fairly long pull already
- run these springs http://www.farmandsandtoys.com/partdeta ... partid=119
- further cut those springs, need testing to make sure slide+spring are heavy enough to prevent runaway throttle
- use a cable luber to fill the cables with a very low viscosity lube
- install a roller bearing throttle tube or bar end roller bearing
.......haven't done the legwork to figure which one works for us if at all
- reroute/recut your tight bend cable portions
- didn't include a slower ratio throttle since ours is fairly long pull already
Andrew
Wolfgang had the same issue as you,
I have remade the throttle cables longer so no tightbends and used 1.5mm rope wire with the outer having a teflon liner, bought parts from 'venhill'
I have also removed a coil and half from the springs, throttle is a lot lighter now
I'm using a domino twin pull throttle assembly
Jetting now 145/148 mains, 48 idles, JJH needles 2nd click from top. air srcrew 1 1/4 out
Pulls alot better still room for improvement
I have remade the throttle cables longer so no tightbends and used 1.5mm rope wire with the outer having a teflon liner, bought parts from 'venhill'
I have also removed a coil and half from the springs, throttle is a lot lighter now
I'm using a domino twin pull throttle assembly
Jetting now 145/148 mains, 48 idles, JJH needles 2nd click from top. air srcrew 1 1/4 out
Pulls alot better still room for improvement
Mediocrity is a sin !
Sorry Andrew the clutch wasnt right when it was dyno'd
so the info isnt that useful
I would agree it may be rich but i'm taking it slow as plugs are cheaper than engine parts, still think it was crisper on the 45 idles, but not always possible to get a reliable tickover
Running foam pod filters
Mick abbey tune
Mick Abbey pipes to suit tune
Heads done by Stan Stephens
Standard (47x) ignition PV control
so the info isnt that useful
I would agree it may be rich but i'm taking it slow as plugs are cheaper than engine parts, still think it was crisper on the 45 idles, but not always possible to get a reliable tickover
Running foam pod filters
Mick abbey tune
Mick Abbey pipes to suit tune
Heads done by Stan Stephens
Standard (47x) ignition PV control
Mediocrity is a sin !
Dubsey, the KX85 carb. comes with an NAPE and the KX100 carb. comes with an NAPF (one step leaner).
I'm not sure of the translation to the Sudco catalog although I'm sure they can tell you how they compare and don't have mine done yet so can't say yet on the NAPE.
Where is your bike running rich in the throttle position and rpm?
I'm not sure of the translation to the Sudco catalog although I'm sure they can tell you how they compare and don't have mine done yet so can't say yet on the NAPE.
Where is your bike running rich in the throttle position and rpm?
Andrew