All 2st Keihin PWK q

I have a PWK 38 S (not AS), I want to put on a 300. Does anyone know the difference between the S and AS and will that S work on the 09 300? It's from an '03 YZ 250

The AS is the air striker version an has the vanes around the air jet intakes on the intake side of the carb. These are supposed to stabilize and increase the velocity of the air at that point and increase the pressure signal. The AS series carbs are of more benefit for smaller displacement engines that do not flow a lot through the carb at small throttle openings.

While I’ve not got a lot of hands-on experience with it, I’m not sure the PWK S will be a whole lot better than the TMX based solely on specifications. For what that is worth…

Yes, the 38mm PWK S will work with your 300 just fine if you jet it properly.

Is it that the TMX is no good, or just hard to jet? The factory jettink kit is supposed to make a big difference. Looks like JD makes one for the 300 too. (Says '08 300, but assume its '09) w TMX
Also, are their any mods that need done for the PWK swap, or just plug n play?

I believe my PWK 38 from the YZ comes equipped with TPS. (i'm not home for a few weeks, but remember a couple of wires/plugs being attached)
If so, will this carb still work for the swap?
Thanks

The '03 YZ came with a PWM, not a PWK. The PWM you have is a very short carb and I'm not sure how it will fit. I was looking at that carb when I still had my WR, but I was going to use a reed spacer from a '01 Honda CR250 to set the intake manifold back enough to make up the gap.

I have a non-airstriker 39mm PWK on my WR 360 and it works very well. My impression is that the non-airstriker PWK still works better than the TMX on the bottom(I have tried both on the 360). The 300 and 360 should both have enough vacuum pressure and low throttle position air velocity to make it work quite well.

I do remember the manual saying it was a Keihin 38 PWK -because I was psyched about it. Made me feel like the WR and I were meant to be!
I just looked up the parts on a Yamaha oem fiche. One of the wires/plugs is a fuel cut solenoid the other is for throttle sensor assy.
Inoticed that the TMX doesn't have those electonic gizmos. Carb should still work properly though, right? Do you think this will be a problem?

The TPS means nothing to the Husky. Just remove it. The shut-off solenoid should be fine if it is normally open.

Saweeeeeet!! Thank you!

Anyone tried a 36?