Kawasaki EX500 Ninja 500r (US) 1987-2009
known as GPz/GPx500 in the rest of the world -
Factory Pro Series "K05"

Classic, simple and reliable, the EX500 is one of the funnest bikes to ride - an excellent first bike and and excellent budget racer. It's relatively mild state of tune just begs for a bit of "tweaking".
The Carb Recal Kit and the Ignition Advance Rotor perks up the low-end and midrange power and response for quicker warm-up and more response. The Transmission Detent Spring Kit really puts "snap" into the shifting.

With the installer's fine tuning, this carb kit will allow the bike to feel better at part throttle - making it more predictable at low rpm.

Factory Pro's own
Supersport Carb Recalibration Kits
carb jetting kit
Factory Pro's own
Ignition Advance Rotor
Factory Pro's own
Shift Improvement Kits
Tuning Tools
Finger and screwdriver adjustable fuel mixture screw kit

Long Boy Extended Fuel Screw
pn: CRZ-SCR-3518k2
 with 2 new extended screws, springs, washers and o-rings

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"Long Boy"
 Finger and screwdriver adjustable extended Fuel Screw assembly

Frustrated with trying to find an "almost 90 degree"  screwdriver to fine adjust your fuel screw for best idle and cruise?
Use Factory Pro's new "finger adjustable" fuel screw to adjust fuel screw for best throttle response. Traveling to high altitude? It's easy to lean out the lowend temporarily.

Make your life easier.

Remove old short stock fuel screw, old o-ring, old washer and old spring. The o-ring might be stuck in the carb, so take a light and make sure it's really out  (or you can't find it after you took out the screw)
Use a small bent wire to pull it out if it doesn't drop out. Keep the old parts for "spares".

Screw assembly kit comes with:
2 new extended screws
2 new springs
2 new washers
2 new o-rings

         Awesome part! Seems like the only ones who make them!  

Carb Recalibration Kits     jet kit

CRB-K05-1.0     $89.95

Use this kit if you are using the

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Standard drop-in carb kit

This carb jetting kit, when properly tuned, adds more low-end / midrange and if the proper main jet is selected, more top-end power. Easy to install and tune - no slide drilling!

The internet's choice........

Why is it that most long time internet groups suggest the Factory Pro jet kits??? They are the #1 performance choice -

From: Peter Jennen, A-1 Lock & Key [mailto:a1lock@bradcowisp.com]
Sent: Thursday, May 17, 2012 10:11 PM
To: marc@factorypro.com
Subject: Ninja 500 jetting.
I received the kit today.  Leigh told me it would have a Keihin needle, but it appears to be yours. 
I wasn't too happy when I looked at it!  It is identical to the stock one for about the first 2/3!  I thought, I'm going to call Leigh and give him a piece of my mind!  Needless to say I was expecting something else. 
But, what I learned is it pays to pay the pro!  I set the needle in the second groove and started out with the fuel screw out 1.25.  I tried different fuel screw settings (from 1-2) tonight and 1.25 ended up being optimum.  I need to make sure the carbs are properly synced before I get too carried away with the pilots.  I think a 38, with the fuel screw at about 1, would be perfect.
What I have is stock main: 130,  your needle: 2nd groove, stock pilot: 35, fuel screw: 1.25 out, 1 hole drilled on left inner rear of air cleaner- across from factory inlet
Altitude 1000ft, 72 degrees, dew point 52 degrees.  Bike runs AWSOME.  At a crack of the throttle the forks extend as the little bike pulls.  One friend described the stock bike as, “willing and eager for a 500".  With the setup I had changed it to (fuel screw out 2.5 turns and the stock needle raised .025 with the “FOG Mod" it didn't have that “willing and eager demeanor".  Now it is running the best it ever has!  The main pull from 7k-10K is really strong.
This little bike sure is fun.
Thanks for doing a good job, Marc!

Response -
Hi Pete,
Shimming a needle a little bit works on some bikes, but only a little bit. But it rarely delivers optimal performance on most ex500's. In some areas, our needle is less than a thousandth of an inch different from stock.
Thanks for the email - we appreciate it -


CRB-K05-1.1-TI  $99.95

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Ti ProKit carb kit

Titanium needles. The toughest material used in a carburetor. These needles will still be around in the millennium after next. Keihin, unlike Mikuni, uses a steel needle jet. Ti and steel, in this application are unbeatable for long life.
The kit, when properly tuned, adds more low-end / midrange and if the proper main jet is selected, more top-end power. Easy to install and tune - no slide drilling!

CRB-K05-3.0   $89.95

For use with POD airfilters
does not include pod
air filters

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Config 30 carb kit

Requires removal of stock airbox and running K&N or equivalent individual air filters. Otherwise, it is a drop-in kit. Low-end response is as good as, if not better than stock carb tuning.

stock carb settings for ex500
(including float height)

Ignition Advance Kits / rotor

RTR-KAW-5-05     $89.95
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Ignition Advance Kit

This simple, bolt-on advance kit advances the timing 5 degrees. With stock engines with stock compression ratios, there is more power everywhere. Part throttle power is better - helping corner exit speeds. Improved in-town drivability and quicker warm-up.

Absolutely REQUIRES an AIR IMPACT wrench to install - If you try using the puller without an impact you WILL strip the puller and the ruin the puller threads in the flywheel!

Shift Improvement Kits

SHFT-PRO-KAW-1   $139.95

(microbearing detent arm and F-Pro spring)

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Premium Pro Shift Kit
(microbearing detent arm and F-Pro Shift Spring)

Make shifting MUCH quicker and virtually eliminate missed shifts. Designed for the EX/GPx 500, this kit virtually eliminates the lackluster shifting action of the stock EX and mandatory for racing or severe use. It's the same type of kit that Muzzy, Vance and Hines, Yamaha Racing has used for years.

SHFT-KAW-1   $49.95

(spring only)

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Basic Pro Shift Spring
(spring only)

Make shifting quicker and virtually eliminate missed shifts. Designed for the EX/GPx 500, this kit virtually eliminates the lackluster shifting action of the stock EX and mandatory for racing or severe use. It's the same type of kit that Muzzy, Vance and Hines, Yamaha Racing has used for years.

Carb Tools

TL-float height gauge   $59.95

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The only way to accurately measure float heights. Works on nearly every carburetor.

True Rear Wheel Horsepower Factory EC997a Eddy Current Dynamometer

ex5forder.jpg (35738 bytes)
1998 AFM #1 500 Superbike Champion
Simon Forder


Absolutely NO carb parts sold in California.

New and improved Suzuki Teka SFI  2

with new TPS display and "MMT" Memory Module Tuner

Finally - Quick, easy, cost effective Suzuki tuning with no expensive "add-on boxes"
Suzuki cruisers and sportbikes

Please click here for more info

Contact Factory Pro
M-F, 9am - 5pm, Pacific time, -7 or -8 GMT

800 869-0497
 USA and Canada

415 883-5620

parts information

EC997 dynamometer information

Product Support /Tech SECTION
click here


Mailing / Shipping address:

Factory Pro
101c Roblar Drive
Novato, CA

And most importantly
Restart back at the HOME page and click on the red box in the top left to find the bike that you want parts for...
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EFI and Carb Tuning - Most all FI and carb tuning

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The extension of the laboratory for engines of the Swiss Federal Institute of Technology was completed in about 1935. Its architect was Rudolf Otto Salvisberg (1882-1940). He had a successful career in Berlin but returned to Switzerland after the advent of the Nazis. His architectural style was somewhat similar to that of Erich Mendelsohn. The staircase of the laboratory is in normal use but well preserved.
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