Suzuki GSX-R750, 90-92
"unrestricted" or "49 state" "38mm carb"
also fits Italy 90-91, UK 90-91 and all with 38mm CV carbs.

(36mm carb - restricted models - in 92 Italy, use "S57" kit with 36mm carbs)

We are proud of this kit - The winner of multitudes of AMA Pro races and the overwhelming majority of amateur races in the United States in that time.
The kit activates the sometimes dormant Powerjet Circuit on some country specific versions and recalibrates it for the other versions, like Canada, where the power jet was activated, but improperly sized.


Scott Hubbard April 2014
Factory Pro's own
Supersport Carb Recalibration Kits
AMA race quality carb jetting kit
billet engine covers Factory Pro's own
Billet Engine Cover
Factory Pro's own
Shift Improvement Kit
Carb Tuning Tools
Factory Pro's own
Ignition Advance Rotor
fixed or patented adjustable types
not Factory Pro's own
Emulsion tubes / needle jets
we may have stock Suzuki replacements in stock

 

Finger Adjustable "Long Boy" extended fuel screws

 

Long Boy Fuel Screw Kit
pn: CRZ-SCR-5020m
replaces 13279-47070
fits both 38mm CV and original Smoothbore carbs

 $89.95
 with 4 new screws, springs, washers and o-rings

1. Choose your shipping method

2.

"Long Boy"
Finger adjustable extended Fuel Screw assembly

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!

Installation:
Remove old short stock fuel screws, old o-rings, old washers and old spring. The o-ring might be stuck in the carb, so, 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 for "spares".

Each screw assembly comes with:
4 Long Boy fuel screws 
 4 new o-rings
4 new washers
4 new springs

              

Carb kits

CRB-S06-1.0  $149.95

for use with the stock airbox.

1. Choose your shipping method

2.

Special fine tuning for these carbs.

Use whatever main that make the bike pull the hardest at 9k-10k. Pay no attention to 12k and 13k.

That's the right main jet.

Adjust the needle for best full throttle 5k-7k power.

That's the right needle height (assuming you did the previous main jet test).

Adjust the float height for the best full throttle / 3k-4k power.

That's the right fuel level (assuming you did the previous main jet and needle testing)

Adjust the fuel screw for best idle and cruise (whatever it happens to be).

If you are 3.5x+ on the fuel screws, you should try a larger pilot jet. If 1.5x or less, you need to try a smaller pilot jet.

Adjust powerjet size for best power at 12k and 13k.

That's how we tuned them and won AMA Nationals.

When it's right for EC997 dyno and real world, and you run them on a dynojet style dyno, it will show an imaginary burble at about 10.25k.   
It doesn't exist in the real world.

 

Today, this kit would be called a 1.7-RK RaceKit in "Factory Pro speak".

This kit activates the Powerjet circuit (if the carbs came with a "zero" sized jet and in countries that have the powerjet circuit already activated, puts the  correct sizes of jets for the proper ratio of both the jet sizes.

If using a dynojet dyno to tune, when you actually have the proper size and ratio, you'll see a distinct "dip" at about 10,000 rpm. That's an artifact of the odd load condition that dynojet dynos are so well known for. If you "tune out" the "dj dip", with a larger main and smaller powerjet, the actual real world performance is dulled, def. enough for a rider to notice the difference. Yes, even as of 2012, a dj dyno still has the same problem.  An EC997 dyno doesn't show a dip.
It has to do with the "quick and short" load time, at full throttle only,  of the dj dyno and the amount of time it takes the carb's pwjt circuit to lift and deliver fuel. The dj load is so short and acc. is so quick, as compared to the real world, that there's a tiny amount of time that it's a bit shy in fuel.
It's not there in the real world or on an EC997 dyno that may be close to you.

Adds more low-end / midrange, if the proper main jet and powerjet is selected, more top-end power. Easy to install and tune - no slide drilling.
Note! When replacing a dj kit with Factory Pro components, be sure to replace the emulsion tubes with stock, Suzuki tubes (available from Suzuki). The dynojet emulsion tubes will not work with standard type replacement needles. The Mikuni emulsion tubes have ID numbers and the dynojet tubes are not marked with any part number.
 

 

feedback

April 2014

Hey Marc, wanted to let you know I got it sorted.   I took them apart again and found 2 choke jets had come out of the plastic tubes where they are seated.  It had this problem when I bought it and I had put them back in but I guess I rattled a couple loose while working on it…   So on top of that here are my new settings in case you’re interested.   Main jet:  127.5 (stock) Needle position:  2.5 (shim under at position 2) Mixture screws:  2 turns out Power jet installed per CRB-S06-1.1-TI kit. K&N filter full system D&D Show and Go exhaust factory pro RTR-SUZ-4 ignition advancer   Pulls hard now at full throttle, no more lean surging at even throttle and no bog and stall at stop lights.  A bit of backfire on decel but not excessive.  Overall better across the range in the seat, will take it to the dyno and let you know what it gets.   Again, thanks for your great products and support.   Scott Hubbard

August 2012

Hey Marc......
I was able to fix that carb (broken powerjet hose barb) with an rd400 oil injector in my scrap bin and it works great!  I just wanted to say thanks again for everything and taking time out to help. Seems like its hard to find people like you these days so keep up the good work! As for the bike I was amazed at how well it runs right out of the box. It is the best this bike has ever ran!!! This is my friends bike and he has owned it since 93. It was 2 years old when he got it and seems like it never ran right. He had some motor work done back then and had several dealers try to tune it to no avail. It was pushed in the corner and still looks new and has not been started in 12 years. I have many bikes and over the years learned all I could to keep them going and felt like I was much farther along now as a mechanic than I was 12 years ago, so I convinced my friend this was the year when he could ride his 91 alongside  my 89 once again! To cut this long story short your kit and advice has made two middle aged dudes feel like twenty somethings again and my friend can hardly contain himself ! I will be trashing the dynojet kit out of my 89 soon for a Factory Pro!                                     Cheers!!!               Ken Crist

 
UK models with 38mm carbs (I think all of the 90-92's had 38's):

UK bikes (and all others with "zero" powerjets) need:

stock emulsion tubes (not dynojet)
Drill the UK's "zero" MAJ's to .9mm in cyls 1 and 4 and 1.2mm in cyls 2 and 3.
37.5 pilot jets (instead of 32.5)
Then our S06 series kit will activate the Powerjet circuit and you will be amazed.
btw - the gsxr750's "Powerjet" jets are the same series powerjets that a Yamaha tz250 uses.

CRB-S06-1.1-TI   $169.95

for use with the stock airbox.

1. Choose your shipping method

2.

Same as above, but........

Titanium needles and Stainless steel allen screws for the float bowls. Adds more low-end / midrange, if the proper main jet is selected, more top-end power. Easy to install and tune - no slide drilling!
Note! When replacing a dj kit with Factory Pro components, be sure to replace the emulsion tubes with stock, Suzuki tubes (available from Suzuki). The dynojet emulsion tubes will not work with standard needles. The Mikuni emulsion tubes have ID numbers and the dynojet tubes are not marked with any part number.

 

CRB-S06-3.0   $149.95

for use with pod filters.

 

1. Choose your shipping method

2.

For the best top-end power (+2-3 True HP). Good low-end and midrange. Requires removal of stock airbox and running BMC 2922 or K&N equivalent individual air filters. Otherwise, it is a drop-in kit.
The powerjet circuit, due to the reduced pressure applied to the pj circuit, doesn't function at the same importance as the kits that use the stock airbox.


Note! When replacing a dj kit with Factory Pro components, be sure to replace the emulsion tubes with stock, Suzuki tubes (available from Suzuki). The dynojet emulsion tubes will not work with standard needles. The Mikuni emulsion tubes have ID numbers and the dynojet tubes are not marked with any part number.

Ignition Advance / Advancer / rotor kits

RTR-SUZ-1   $109.95

1. Choose your shipping method

2.  

This standard kit rotor advances the timing 1.5 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.

F-Pro Shift Kits

SHFT-PRO-SUZ-3  $139.95
F-Pro steel microbearing detent arm, F-Pro shift spring, oil pan gasket


(add $20 for Hybrid ceramic bearing upgrade)

("Legacy kit" - allow 2 weeks for building)

1. Choose your shipping method
 
2.

Microbearing Trans Detent Arm and Spring and oil pan gasket kit

Make shifting quicker and virtually eliminate missed shifts. This is exactly the same type of kit that Yamaha Racing has used.

Note:
This kit will not fix a damaged transmission - If the bike is constantly kicking out of second gear, you really need to split the cases and replace 2nd gear, the gear it mates with and the second gear shift fork.

 

NOS-Suzuki-Shift-Shaft-Spring-GSX-600-750-1100-GSXR-750-1100-09443-09031


SHFT-SUZ-3  $54.95

F-Pro shift spring, oil pan gasket

1. Choose your shipping method
 
2.

Trans Shift Spring and oil pan gasket Kit

Make shifting MUCH quicker and virtually eliminate missed shifts. This is exactly the same type of kit that Yamaha Racing has used.

Note:
This kit will not fix a damaged transmission - If the bike is constantly kicking out of second gear, you really need to split the cases and replace 2nd gear, the gear it mates with and the second gear shift fork.

Emulsion tubes / needle jets

Needle jets

Needle jet
(also called emulsion tube)

Sorry, Factory Pro DOES NOT manufacture replacement needle jets (also called emulsion tubes) for these 38mm carbs.
The needle jet orifice wears oblong in as little as 5,000 miles and is particularly aggravated by "in town", low rpm operation. The result is excessive richness at low rpm that can be partially compensated for by lowering the fuel level. Inspect and replace needle jets (emulsion tubes)when required.
Sometimes we DO have Suzuki units in stock, though.

415 491-5920

Suzuki part number:   .JET, NEEDLE (O-8)      09494-00677

 

carb tools

TL-float height gauge
$59.95

1. Choose your shipping method

2.

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

How to set floats

 

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

415 491-5920

parts information
 info@factorypro.com

EC997 dynamometer information
info@factorypro.com

Product Support /Tech SECTION
click here

 

Mailing / Shipping address:

Factory Pro
179 Paul Drive
San Rafael, CA 94903
USA

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

 

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LINKS
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Flight Training - train with AMA race winner Todd Harrington.

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 8 locations

 800-362-0808
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. 
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It doesn't matter what you ride or race, the Rich Oliver Mystery School improves everyone's skill level and mindset!

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(NEW!  Ask about the P-40 flights!)

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Just tell them that you saw this on the Factory Pro website!
Marc
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.