2010 carb question

[GG27]

Today I was riding with a EC 250 2010, really beautiful bike. I noticed that the 2010 models have a different carb. The particular bike was running perfect, really crisp with lots of power, rider had factory settings. was going up and down steep hills with no issues. What is this carb and what would be the major differences with the PWK?

[MattR]

I didn't notice it before in the 2010 pics. I looked on the GasGas website and it is only called out as a 38mm carb (no model name). Here is a close-up of the new carb. It has a remote choke cable hooked up to a lever on the clutch perch (like a hot-start mini lever on 4T bikes). The top of the carb looks more rectangular than the older PWK style (round). I'm curious what model of carb this is. It's hard to read the logo, but is this a Mikuni TMX38 carb???

[GG27]

IMHO it looks like the KEIHIN the KTM's have. I read that the racing versions have it since 2009. Nombatim's bike surely had it. What impressed me was the crisp response and the way it went down long steep hills without stalling!

[Catarallus]

The carb is called Keihin PWK-S 38 AG. But i don't know the differents between the "old" and the "new" carb.

[Ud_luz]

It's used on the KTM 150sx. The top is held on with allen bolts. I wouldn't mind trying one. I've been told the 150sx is virtually flawless carb wise.

[RBD]

Originally Posted by Catarallus

The carb is called Keihin PWK-S 38 AG. But i don't know the differents between the "old" and the "new" carb.

I call it a short body PWK and they are 15 mm shorter from front to back of the carb spigots. They use all the same internal parts as the longer body PWK, slide float assy, bowl and jets, etc.

The short body PWK's also have a o-ring on the mixture screw, but the mixture screw is the same.

It is my opinion that they use a short body for room issues as there is not a lot of room for a carb, mono shock and a air box in a small package.

Ron

[GG27]

If the new carb is exactly the same internally as the old one, and there is no space problems why did they change it?
I think you can change the pilot jet on these carbs just by removing the 17mm drain plug as on my Yamaha YZ250, also the needle clip had a rubber gasket to reduce vibration.

[iancp5]

Originally Posted by GG27

If the new carb is exactly the same internally as the old one, and there is no space problems why did they change it?
I think you can change the pilot jet on these carbs just by removing the 17mm drain plug as on my Yamaha YZ250, also the needle clip had a rubber gasket to reduce vibration.

Have they changed the reed block / spacer etc?
If they just allow the carb to be removed easier with the airbox in situ it's worth it. KTMs seem to have better fuelling, especially idle, thought maybe they had better tolerances on their squish?

[300XCRider]

Looks like the carb on my '09.

[RBD]

Originally Posted by GG27

If the new carb is exactly the same internally as the old one, and there is no space problems why did they change it?
I think you can change the pilot jet on these carbs just by removing the 17mm drain plug as on my Yamaha YZ250, also the needle clip had a rubber gasket to reduce vibration.

The YZ carbs that I have worked on use a spring and bushing damper on the needle.

Yes, they did move the drain plug on the float bowl to allow excess to the pilot jet and main jet.

I wonder if gasgas will ever try the electronics on the carb like the YZ's and Kaw's?

Ron