Kawasaki Ninja 250r  (usa)
EX250 ZX250  (uk)
2008 2009 2010 2011 2012

(not 2013 and later)

Great in-town bike and a fun entry level racebike for areas of the world that have a 250 Production race class.

The 2008-2012 features great, all new styling and subtle changes in the power producing plant to provide a more lowend and midrange, a quieter engine and decreased exhaust emissions to prevent Al Gore's Global Warming.

Little known fact - Factory Pro has built quite a few race winning EX250 racebikes. Porting, milling, boring, Full Radius Valve Jobs were available for the 250. We specialize in custom tuning the EX's - whether we built the bike or not.

To extract the maximum power for the engine, it is necessary to use the Low Inertia EC997 Tuning Dynamometer with 4 Gas EGA to concurrently dial in the carbs and the cam timing. You can't really do optimum work on an inertia dyno, socalled "tuning to an af as is usually found at dealerships levels -


EX250 during oil additive testing on EC997 Eddy Current Dynamometer by Factory Pro

Unleash your bike's power and control
F-Pro Shift Spring  -  Shift quicker and virtually eliminate missed shifts

Blue Magic Shift Spring
pn: z95-k25-045
(replaces 92144-1580 kaw spring)

$20 + shipping
(yes, in good humor, it's $14 for UPS Ground, even for a little blue spring - and we have to ship it tracked and insured and no, I can't just drop it in the mail and hope and wish you get it and no, I can't afford to send someone down to the post office to mail it Priority tracked and insured)

or you could pretend it's:

$34 and Free UPS USA ground shipping!
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talked to a guy who said this spring worked really well. Actually said he cut over a second from his lap times just because he didn't have to worry about missed shifts anymore. He said he told all his friends to get one.
Leigh Thomas
Feb 2015

From Factory Pro - the originator of motorcycle shift kits.

Blue Magic Shift Spring

Improve lazy shifting - virtually eliminate missed shifts - virtually eliminate false neutrals -  help prevent gearbox damage caused by missed shifts.

Countless hours of thought went into this spring's specs.

"The Blue Magic Shift spring"

Positive feedback rating

This kit includes the new F-Pro Shift Spring.
That's it. A carefully fabricated and heat treated spring.

1-2 minutes to install.

1. Remove bolt and old spring.
2. Replace old spring with New Blue Shift Spring.
3. Replace bolt.
4. Shift better and find neutral easier.

Hybrid Ceramic Wheel Bearings
5 bearing kit
pn: BE-HYCER-K04
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Hybrid Ceramic Wheel  Bearings

5 bearing set

2 front wheel bearings
2 rear wheel bearings
1 sprocket carrier bearing

Special Pricing

Tough steel races and almost  friction free trisilicon tetranitride ceramic balls.

Bearings are pregreased and ready to use.
Bearings have rubber seals that are easy to remove if desired.


Test ex250:  +1.5  /  5% at +100 mph
Carb kits
Stage 1 / Config 10 Carburetor Recalibration Kit for:

stock or aftermarket stock replacement air filter
stock or aftermarket exhaust slipon or complete system
snorkel installed or snorkel removed

When you desire to use the stock airbox with stock or K&N air filter.


EX250  2008-2009-2010-2011-2012

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rop-in kit, using the stock airbox and
 stock, K&N or UNI stock replacement air filter. 

 The kit has enough jets to use with an aftermarket "street" or "race" exhaust - and also, the stock exhaust.

No slide drilling, like the dj kit, is required.

inc: a selection of main jets, pilots, Celmat30 needles, clips, shims, float bowl allen screws, etc.

Feedback from 250 users in the real world
email your results -
click here
exhaust air filter snorkel? Ignition advancer
main jet main air jet (advanced tuning) needle height float height pilot fuel screw turns out elevation temp
humidity installer / date
Musarri slipon muffler K&N snorkel removed no 100
(but did not try 102)
stock /4 + 3 shims as delivered 40 2.5x to 3.0x <500ft 70f to 90f 18c to 30c 20-30% Chris Bright
May 2013
Musarri slipon muffler K&N snorkel removed no 100
(but did not try 102)
stock /4 + 3 shims as delivered 40 2.5x to 3.0x <500ft 70f to 90f 18c to 30c 20-30% Chris Bright
May 2013
Area P exhaust system BMC snorkel installed no 90 stock /3 as delivered 40 2x 300ft 70f to 90f 18c to 30c 20-30% Abhijit Das
Thunderhill Raceway
Akrapovic slipon stock installed no 92 stock /3 ? 40 about 2 sea level 60f to 80f 15c to 27c 30% Moto-tecr 2010 April
Yoshimura full system stock removed 90 stock /3 14mm 40 about 2 sea level 60f to 80f 15c to 27c 20% to 30% The
2008 August
Area P system stock in place 92-95 stock as required ? 38 / 40 about 2.25 <500 ft 60f to 80f 15c to 27c around 20% Carry Andrews
Project bike
2008 July
Stage 3 / Config 30 Carburetor Recalibration Kit for:

1 RU-0990 (1 RU-0990 covers 2 carbs) air filter
stock or aftermarket exhaust slipon or complete system

When you desire to use
individual air filters or R-0990
remove the airbox.

 air filter


When you desire to use
single dual air filter R-0990
and remove the airbox.

ru-0990 air filter

EX250 08-12
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EX250 08-12
 CRB-K04-3.0 with filter
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Feedback from real 08-12 250 users in the real world
email your results -
click here
bike exhaust air filter Ignition adv
pilot float height needle ht main jet main air jet elevation temp
humidity installer date
08 ex250 full system BMC
2 x 50/70
40 as delivered /3 115 stock sea level 59f 15c 20% WSR 2008


Long Boy Extended Fuel Screws

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

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"Long Boy"
 Finger adjustable and screwdriver 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  Long Boy fuel screw  CRZ-SCR-3518k2
2  new o-ring
2 new washer
2 new spring

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


Carb top Allen Screw kit

Carb top Allen Screw Kit

7pcs 10mm shouldered 4mm Allens
1pc 4mm x 16mm allen screw (for choke bracket)



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The MUST HAVE tool for measuring float heights to make lowend as perfect as possible.

TL-float height gauge    $59.95

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The easiest way to set float height - important when tuning for max mileage and low rpm tuning precision.

click here for "how to"

2009 Ninja 250
We bought it used with 2500 miles on it. 
Warm up took an excessively long time. Hesitations were excessive. Only when fully warm did it run OK.
After installing your jet kit to your specification (the only thing I did different was start with the 90 main) the bike started immediately. It had never done that before. I was able to turn the choke off quickly. Moments, not minutes. Performance was flawless even before warming up. This is how it should run. 

air filter: Stock
snorkel?: Stock
Ignition advancer: Stock
main jet: 90
main air jet (advanced tuning): stock
needle height: 3rd down + 3 shims on top
float height: as delivered
pilot: 40
fuel screw turns out: 2.5 turns (both)
elevation: 758'
temp: 20f to 90f
temp: < -6 to 32c
humidity: 53-83%
installer /: Steve Baumann/Columbia MO USA
date: January 16 2020

Thank you for the great product!
Steve Baumann


Oil Additive

$30 / 4 oz bottle

Anti Friction
4 oz treats 3 to 5 qts synthetic oil

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As I recall -

After running over 100 AMA and WERA bikes, we gained from 2% to 3% power,

The least I saw was 1% (JR's super loose built engine) and the most I ever saw was 4% (on a super tight street  built engine).

The other 98 bikes picked up 2% to 3% power - with most 2% and  2.5%

Lasts 2 and up to 3 oil changes (tapering off in effect).

Helps highway mileage.


Ignition Advancer kit

RTR-KAW-5-05     $69.95

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Hi Marc,

today my Kawa-Center installed the ignition advancer kit.

This is amazing, unbelievable how my engine runs now. I'm very happy
that I'd bought the ignition kit, it's a big advantage.

Great work from you.

Have a nice day and best regards,


This is an easy power and mileage increaser.

Ignition Advance Kit -
(but does NOT include the 250 flywheel puller - a dealer can install in around 1-1.5 hours.)

Better "off-corner" power and some full throttle power and extends the power band  500 to 1000 rpm - Increasing overall average horsepower.

 We do not make an ignition advance kit specifically for the ex250, but this ex500 kit has the magic piece that works on the 250 also.

The ex250 uses a large, 3 bolt flywheel puller that only a dealer would have.
The woodruff key from the RTR-KAW-5-05 is the right key that fits the 250.....

If you buy the RTR-KAW-5-05 kit, you can use the supplied woodruff key and the installation instructions for the ex500.



July 24, 2012

After talking to Factory Pro on my on-track experience at the racetrack; and knowing we have the best jet sizes in, I still wanted a better throttle response. Now, as a novice racer I did not want to dump in huge dollars (specially at a club racing level) just to squeeze the extra horses out of this small motor. 90% it has always been the rider than the bike. Marc suggested I should go with the ignition advance kit Factory Pro developed. We got the key installed, did a dyno but at the end it matters how the bike feels at the racetrack. I rode at Thunderhill this Monday and I was amazed by the throttle response and how crisp it is. I also felt the throttle came to my hand much much sooner. At some corners, I had to back off so I was not constant on the redline wherein the motor would cutoff, thereby I was modulating and now I did not have to. I am very happy with this modification and thanks to Marc and his team for the number of years they have put in researching this and applying their racing experience to develop a great product.

Abhijit Das

July 31, 2012

I ran at Thill again on July 30 (Monday). And, I finally got used to the new rpm range and response. Love the additional 1k.

Abhijit Das


creighton smith wrote:

I really enjoyed swapping flying tales last week but what I really enjoyed was taking my bike for a ride on Saturday after installing your jet kit.
I started off with some trepidation since the 250 Ninja board is chock full of horrifying stories of repeated rejettings, needle raisings and lowerings and all manner of, after all that, very partial successes.  None of these concerns Factory Pro kits, however, and for good reason as I discovered.
I installed everything per the instructions:  3rd groove, install jets, 2 turns out (went out another half turn), and the bike ran well from the get-go.  I now have a midrange, thank you, and find myself cruising around at 7k (even as low as 4-5k if I'm trying to be really quiet) which is something the stock setup would not allow-at any rate it would not pull smoothly below 8k previously.  Full power is as good or better (My ass dyno is out of calibration, due to a boating accident I missed last year completely.)
I am delighted.  My brother in law is also convinced and may have ordered a kit already.  I'll post a recommendation on the Ninja site, but they're such bucks-down squids they'd rather waste the whole riding season than spend the bucks and the hour to get a fine running bike.
Thanks again.
Creighton Smith




Absolutely NO carb parts sold in California.

New and improved
Suzuki Teka SFI 2
with new TPS display and "MMT" Memory Module Tuner feature

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

no fax

Factory Pro
101c Roblar Drive
Novato, CA

If it's
4pm at Factory Pro it's 9am in eastern Australia.

parts information

EC997 dynamometer information

Product Support /Tech SECTION
click here

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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