Need a new carb for your KX500?

[Sandblaster]

Need a new carb for your KX500?

Looking at Adam MillAr's flow bench numbers and info gathered from Kawasaki Team Green Mechanics we have come up with the following..

96-97 KX250 or a 99-00 Cr250 carb.
Or you can go to Sudco and get a Keihin Quad vent Air striker 38mm for about 300.

You can use the newer Airstrikers as well but you need to block off a few things.

It will add 1 hp to the rear wheel on a completely stock KX500.. That is dyno confirmed.

The flow bench shows that it does just as well as a 41mm Airstriker for volume and velocity. That is also dyno confirmed...

We need to come up with some decent jetting specs.

Sean Colliers bike.
pilot 55
main 175
16009-1613 NEEDLE-JET N89D - 2nd position
Slide 7

We ran this at Glen Helen 1700-1800 ft.. 50% C12 and 50% 91 California pump gas.

You will need the correct throttle and cable for which carb you choose.

[moto939]

Thanks for the info.

Do you know the difference between the N89D needle you used and the stock N82M needle?

Once it stops raining and snowing around here, I plan to get some actual time on the bike and figure out the jetting with the stock carb. Once I get a baseline and a good feel for it, I try a short body A/S from a YZ250 (powerjet blocked off). I also have a #8 slide I might try if time permits.

Basic specs

Bone stock motor
Rad valve with spacer
1600 ft
50/50 VP110/non ethanol premium

[Sandblaster]

The N89D fattens up the midrange.
Most of the guys are experimenting with richer slides and leaner jetting..
I think in the 5 range....
I have only ran the 7
I want to try a short body version....

[moto939]

Good info....I have to remind myself, what works in a 250/300 doesn't necessarily work in a 500. I've got a #6 slide kicking around somewhere.

Too many variables, not enough time!

[Sandblaster]

Isn't that the truth... I could play with my toys all day long if I didn't have to work...

[Sandblaster]

Hmmm... I'm having some strange thoughts..

KX GURU RACING 2016 KTM 250SXF KX500 CONVERSION 183.jpg (298.68 KiB) Viewed 9356 times

KX GURU RACING 2016 KTM 250SXF KX500 CONVERSION 184.jpg (242.54 KiB) Viewed 9356 times

KX GURU RACING 2016 KTM 250SXF KX500 CONVERSION 185.jpg (310 KiB) Viewed 9356 times

KX GURU RACING 2016 KTM 250SXF KX500 CONVERSION 186.jpg (258.87 KiB) Viewed 9356 times

[Sandblaster]

I just need one of these..

KX GURU RACING 2016 KTM 250SXF KX500 CONVERSION 187.jpg (63.07 KiB) Viewed 9354 times

[moto939]

Have you tried test fitting this carb? If you have not, you'll eventually find an interference issue with the tank and the carb cap.

Shouldn't be a huge deal to modify the cap since the tps is removed from the carb. I'm hoping that's all that's needed.

[Sandblaster]

The short bodied carb I have not tried it just yet.
It's still sitting about a foot from my computer
I have so many project going on right now it's crazy.
KTX500E
Sean Collier's engine.
Sean Collier's rear brake mod.
K5 trans mod.
K5 drum valve mod.
K5 Turbo crank mod.
K5 92mm Big bore Mod.
And probably a few others if I were to take a look around my shop

It will fit my KTX500E with no issues as I have a ton of room.
But my basic K5 may have some issues..

The 96-97 KX250 and 00 CR250R carbs ( 38mm quad vent air striker) will fit with no issues as one is on Sean's bike right now..

[moto939]

The carb fits fine, other than the cap hitting the inside of the tank on the left side.

The welch plug area will need to be removed and tapered back towards the cable in the center......or at least that's the plan.