Yamaha yzf750r, 93-99

Ivan Finiti - Spain - winner 2019


Factory Pro's WERA and AMA National winning
"1.7-RK" carb kit
The absolute best carb kit ever made for the yzf750

Factory Pro's
Pro Shift Kit

Better shifting than some new bikes for your yzf.
Factory Pro's own
Emulsion Tubes
Like new performance for a classic winner
Kowa Seiki
Float Height Tool


prid94_1.jpg (124736 bytes)

Jason Pridmore on Team Kinko's Yamaha YZF750

Yamaha yzf750 (93) 94-99

Yamaha has almost always made sportbikes that outhandled, out of the box, most any other sportbike. The yzf 750 was no exception. Easy to setup and ride, a nice one still is a sweet handling bike - even in 2010. Sure, there were some Yamahas that missed the mark in the handling area (and I got to race a couple) - but all the yzf 600 / 750and xj 550 / 600 models were simply sweetly balanced machines. 

Ahh.. I remember the sweeeet 110mph, 2 wheel drifts in the old turn 10 at  Sears Point Raceway (Infineon, now..)

But.... on to your bike.......

The YZF750 had a 2-3 hp problem with the high rpm fuel curve.

The carburetor would "lean out" (cutting a few hp) as the rpm increased to redline. Increasing the main jet size helped the high rpm lean problem, but made it too rich at 9k-10k rpm (losing power). The #1.7-rk RaceKit flattens and corrects the fuel delivery curve, preventing high rpm power loss.

The debut of he Factory Pro yzf750 "1.7 RaceKit".
It was first used to win the A Superstock (1100cc class) WERA National Championship at the 1994 Grand National Finals at Road Atlanta by Thomas Wilson, riding the Scott Beach / Michael Tjon tuned, Team Kinko's YZF750r. The 1.7-RK RaceKit was later used by AMA Supersport racer, Anthony Lupo, who rode for us and also used on Tom Kipp's Vance and Hines yzf (a formerly "big secret" - but an ex team member related the story of how they got our kit ).

We happily helped carry Yamaha's flag, with a small investment from Yamaha, and did very well, with creative ideas, hard work and good R&D using the EC997 dynos - and we were happy to do it.  In 2006, Yamaha did very well, with a lot more of their money...... We later did the same quality work for Italy's Belgarda R6 Yamaha bikes when they had the fastest 600 World Supersport bikes.

Factory Products Available

Finger and screwdriver Adjustable "Long Boy" extended Yamaha fuel screws

Long Boy Fuel Screw Kit  $89.95
pn: 3020m1

 with 4 new extended screws, springs, washers and o-rings.

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"Long Boy"
Finger and screwdriver adjustable extended 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!

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 jetting kits, yzf750

CRB-Y73-1.7-RK  $289.95

Vintage Perfection!

usa bikes w n208099 press in main jets

email marc@factorypro.com for non-usa bikes w n100604 large, round, slotted main jets.

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1.1-ti carb kit Feedback:

I messed around with it today, and got it all set.
I had the120 jets in; and 14mm, 3 turns....turned out to be somewhat rich across the entire range. I did not recognize it, due to not having any "spot" where it was an issue, and it did not do any of the standard symptoms.

I put in the 117.5 jets, 15mm fuel height, and 2.75 turns on the pilots. Now it rips, like it has never before. All previous issues have disappeared completely and the power delivery is exceptional.


1.7 RaceKit - this is the right kit to buy.

Would you imagine that you could buy the exact same carb kit  that helped the AMA stock class Yamaha 750 win the 1100cc "A Superstock" WERA National Championships in our own Team Kinko's bikes in 1994 with Thomas Wilson riding at Road Atlanta?
The exact same carb kit that V and H rider, Tom Kipp, used in his dynojet sponsored AMA winning bike? In 1995, an ex VHR race team member confessed that they, mid year, had somebody else buy our 1.7-RK RaceKit and change the cam timing to what we told them, at the beginning of the year  :-)

We could even tell you that the best cam timing on that bike:
with a stock cylinder head -  106-108lc intake and 101lc exhaust and with a full radius valve job, the bike wanted 104lc intake and still, 101lc exhaust. 
NOT 105 / 105.

Could even let you in on a clutch basket mod to stop the chattering under hard launches (look in our Tech Section for chattering clutches).

This "1.7-RK RaceKit" requires some drilling and tapping to install, but easy to do with hand tools. Use with stock or aftermarket exhaust. This carb kit makes best power, overall. At every rpm. Period.

Was used by every top Pro AMA yzf750 roadracer and absolutely the best performing kit for on and off track use. Best low, mid and topend power. At the end of 94 - absolutely no top AMA Yamaha teams were using any carb kits developed on a dynojet dyno (that's a hint about dynos)

When properly tuned, this kit produces the best low-end and midrange possible - and adds 2-3hp to the topend power and revs even higher before dropping off.

This is the ONLY kit to use.

yzf750 tuning story or "Why some it's hard to believe some people."

TECH Notes:
1. Check needle jets for wear!
2. EXUP motor (or similar) MUST be attached or engine will not rev above 4000 rpm

Make float height setting easier! Pick up a Float Cage Holder for Mikuni 38mm carbs  -  See below-

Ivan Finiti - #11 - winner - 2019 - Spain

 New main jet o-rings 
12 pcs
Mikuni # 007-790

$10 for 12 orings
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o-rings for Mikuni
"press-in" n208099 main jets.

If you are jetting older carbs, it is a good idea to get new main jet o-rings when buying a carb kit.

CRB-Y73-1.0  $139.95
(if using the stock airbox)

usa bikes

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1.0 "Drop-in" kit - no drilling
Standard Drop-in kit.

The kit, when properly tuned, adds more low-end / midrange and if the proper main jet is selected, more topend power. Easy to install and tune - no slide drilling!
Make float height setting easier! Pick up a Float Cage Holder for Mikuni 38mm carbs  - Click here

TECH Notes:
1. Check needle jets for wear!
2. EXUP motor (or similar) MUST be attached or engine will not rev above 4000 rpm

CRB-Y73-3.0  $149.95
(if using pod filters)

usa bikes

1. Choose your shipping method



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.
Make float height setting easier! Pick up a Float Cage Holder for Mikuni 38mm carbs  - Click here

TECH Notes:
1. Check needle jets for wear!
2. EXUP motor (or similar) MUST be attached or engine will not rev above 4000 rpm

Emulsion tubes, Factory Pro, nickel plated stock replacement


Needle jet -
our # crz-emu-100120
(also called emulsion tube)
yam pn: 3GM-14141-90-00)
yam pn: 3GM-14141-92-00)
yam pn: 3GM-14141-94-00)

$132 / set of 4
See desc. to right>>>>>>

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Factory Pro manufactures stock replacement needle jets!
(called emulsion tubes by some) to original factory specs.

The needle jet orifice wears oblong in as little as 10,000 (but commonly 20,000 miles) miles and is particularly aggravated by "in town", low rpm operation. The result is excessive richness at low rpm that can only be partially compensated for by lowering the fuel level.

A direct replacement for worn, original items. Accepts standard standard Yamaha jetting and our Factory Pro Carb Recal Kits.

Also fits other bikes with 38mm downdraft Mikuni carbs, such as Ducati, TDM 850 / TRX 750 and 800, fzr1000 (89 and up, but not including the Thunder Ace).

needle jet desc

Float bowl gaskets

reference: 3gm-14997-00-00
$32 for 4
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Transmission Shift Improvement

SHFT-PRO-YAM-4   $139.95

F-Pro Microbearing Detent Arm and F-Pro Shift Spring and clutch cover gasket

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Shift Pro Transmission Detent Arm Kit

Includes Factory Pro Microbearinged Detent Arm, slightly heavier duty detent spring and gasket. Makes shifting more positive at the expense of slightly stiffer shift lever action. The stronger detent spring rotates the shift drum faster, so the gears are more likely to engage under quick shift conditions. The Microbearing removes friction for the quickest shifting.

Yes, that's what we all used in 93-94 to make shifting super slick! The kit will make the yzf 750 shift better than quite a few 2018 bikes.


The pivot screw screws into a raised boss in the crankcase.

Hybrid Ceramic Wheel Bearings

intro special

reg $553.90

5 bearing kit
2 front and 2 rear wheel + 1 sprocket carrier
pn: BE-HYCER-Y73

(allow up to 2 days to 2 weeks for special assembly)
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Hybrid Ceramic Wheel  Bearing kit

5 bearing set

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

Tough steel races and almost  friction free ceramic balls.

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


415 883-5620

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

YZF 750 references:
D and D, Team Kinko's, Vance and Hines, Tom Wilson, Jason Pridmore, Scott Beach, Robert Nutt, Tom Halverson, Jim Leonard, Tom Kipp, Anthony Lupo, Mark Cassina, Scott Ruehle


Float Height Setting Trick for 38mm "Mik's"
One of the problems with setting the float height on the 38mm downdraft Mikuni's that come on Ducati's, yzf 750's, tdm 850's and fzr1000's, is that the darn white plastic "float cage" keeps popping out of the carb body unless you hold it in.

When you hold it in with your fingers, you always flex the cage frame and distort the reading that you are setting the float height at..... Aaarrggghhh!!  :-)

After spending 45 minutes setting some yzf750 carbs in the sweltering Mid Ohio heat of summer, I decided to make a float cage holder and sell 'em! I'd make a million  $$!!

When I got back to work, I set up and made a pile of cute little flat braces.

As I was sitting there, admiring my cleverness...... one of my parts guys wandered by and asked what was I making? I showed him that you could just take my clever little piece of aluminum and hold those float cages right tightly up into their seated position - so you could get consistent float height readings.

He says.....
It looks like you could just put the float bowl on with the front holes on the bowl lined up with the rear holes on the carb body and slap some screws in and it would do the same thing...........
I bought him lunch with the million $$ I didn't make....



Hello.  Here’s the pics you asked for!  Thanks for the help, the bike runs BEAUTIFULLY now, lots more power!  The front end now comes up on the throttle – whereas it didn’t before!  There’s another pic in there too where I used a bar code to measure the bowls.  I found this a lot easier than using a ruler.  I measured the bar next to the number “8” on my barcode to be the recommended height on my bike – 14mm.

-Mike Beary

Thanks Mike, for the pics!
Marc Salvisberg





Absolutely NO carb parts sold in California.

New and improved Suzuki Teka SFI  2

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

800 869-0497
 USA and Canada

415 883-5620

parts information

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Product Support /Tech SECTION
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Factory Pro
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Novato, CA

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Flight Training - train with AMA race winner Todd Harrington.

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 8 locations

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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!  

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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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