DRZ400S  03-20 with CV carb

DRZ400 e (off road CA) 03-07 with CV carb

 Kawasaki KLX400  with CV carb 03-12


"Long Boy"
 DRZ400 extended finger adjustable Fuel Screw.
The new Factory Pro updated DRZ400 Carb Recal kit!
Including Super Moto.

Extended Fuel Screws

Long Boy Fuel Screw

pn: CRZ-SCR-4030m/drz400/klx400

New finger adjustable screw, new plated spring and washer and new o-ring

1. Choose your shipping method


"Long Boy"
 DRZ400 / KLx400 (with CV carb) extended finger adjustable Fuel Screw.

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

Make your life easier on the trail.

Remove old short stock fuel screw, old o-ring, old washer and old spring. The o-ring might be stuck in the carb, so, if it's not in your hand, take a light and make sure it's really out if it didn't come out with the screw (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 in a zip lock baggy for "spares".

1 DRZ 400 / KLX400 screw assembly comes with:
1 Long Boy fuel screw   CRZ-SCR-4030m/drz400
1 new o-ring
1 new washer
1 new spring

      Great product, best price around for these and fast shipping!    Thanks   Blargins


Carb Recalibration kits


Use with a stock or modified airbox and stock or aftermarket exhaust.

1. Choose your shipping method


The Factory Pro updated DRZ400 Carb Recal kit! Including Super Moto

Specially developed to address the cv carb "bog" issues.

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.

It's not recommended to cut additional holes in the airbox, as the main air correction circuit is affected - causing either a lean spot at 8000 rpm or a rich spike at redline. Most Factory Pro Dyno Centers have the equipment to measure the skew and can perform corrections to the main jet fuel curve to gain all the power that the additional air will supply.
Without that correction, you'll always have to "split the difference" and not have all the power you could have at 8000 or at redline.


The arm with a Steel microbearing and spring kit.

$139.95 retail

$99.95 Sale!

(replaces 25350-29F00 detent arm and 25355-29F00 stock spring)

1. Choose your shipping method



Factory Pro Shift Kit

Virtually Stop missing quick shifts.

Includes Factory Pro Microbearing Detent Arm, heavy duty detent spring but not a clutch cover gasket. Makes shifting more positive at the expense of slightly stiffer shift lever action. The stronger detent spring rotates the shift drum quicker, so the gears are more likely to engage under quick shift conditions. The Microbearing removes friction for the quickest possible shifting with the least amount of effort.

Includes: Factory Pro Microbearing Detent Arm, Factory Pro Shift Spring.

Our 2 piece kit includes microbearing detent arm and F-Pro Shift  Spring.


Takes about an hour to install and you have to supply a new clutch cover gasket. You have to be able to remove and replace the big clutch basket to install the new arm and spring. Helps heaps to have an impact wrench.


Tools : diagnostic and setting

TL-float height gauge   $59.95

1. Choose your shipping method

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


August 2005

Hey Marc,

Raul put the cover on the drz400sm this morning, and I thought these photos were probably better quality than his phone-camera thingy. Thanks for making great product, and having great people work for you. The bike runs killer, Raul did a fantastic job tuning it, and I'm loving riding it. Need to get back on the bicycle, though...
Later, Tim


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...
restart at HOME page


This Tuning Site has been visited by
www.digits.net - the oldest counting service on the web





EFI and Carb Tuning - Most all FI and carb tuning

by Wheelsmith Racing

Flight Training - train with AMA race winner Todd Harrington.

The Harringtons own American Flyers, one of the most established flight training facilities in the USA.

 8 locations

The Rich Oliver Mystery School will help you discover your hidden inner strength. 
It will challenge you. It will teach you a new way of thinking, and a new way of riding. You can take your riding to an exciting new level!  

We use a variety of proven drills and training techniques. 
Practicing these techniques with our Yamaha dirt track trainers will enhance your abilities both on the track or the street.  

It doesn't matter what you ride or race, the Rich Oliver Mystery School improves everyone's skill level and mindset!

WW2 vintage flying Special

Book a sightseeing flight over the Wine Country or a Kamikaze aerobatic flight or a biplane flight over famous Sonoma Raceway, the Golden Gate Bridge and the San Francisco Bay for one or two during the spring and get a free souvenir t shirt!
(NEW!  Ask about the P-40 flights!)

707 938 2444

Just tell them that you saw this on the Factory Pro website!
Northern California's most unforgettable flying experience.  No experience required.  Open weekends!

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.
Edited to the tunes of Chemical Residue by Herbie Hancock.