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?
2010 carb question
- Thread starter GG27
- Start date
MattR
Super Moderator
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???
Catarallus
New member
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
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.
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
New member
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
New member
Looks like the carb on my '09.
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
IMHO I don't think gasgas installed this carb for space reasons. I didn't have a chance to ride the '10 250 but it certainly was running excellent, with immediate response and was as fast as my '08 with ltr powervalve cover, fresh piston, jetted spot on, matched transfers 13/50 gearing etc, and both 250's were quicker than a '09 300 racing with stock engine and gearing which was racing in our practice track.
2010 carb
just got a new 09 300 3 wks ago has this carb rode it around the yard in 40 degree weather 1st ride felt lean so looked inside had a strange number needle and clip at top. wanted to ride the next day , no time to rejet so took my rb carb off my 03 has 42 180 eck needle and runs ,perfect put it on my 09 runs perfect !! so last week sent the new carb to rb to do his magic should get it back this week will post after a few rides! but the 09 has a great motor its like an electric motor i think its going to be a great ride. oh not sure this means anything but the old carb cannot be rotated on the bike for jet changes ,the 09 carb can !! gasgas forever!! thanks for a great site
just got a new 09 300 3 wks ago has this carb rode it around the yard in 40 degree weather 1st ride felt lean so looked inside had a strange number needle and clip at top. wanted to ride the next day , no time to rejet so took my rb carb off my 03 has 42 180 eck needle and runs ,perfect put it on my 09 runs perfect !! so last week sent the new carb to rb to do his magic should get it back this week will post after a few rides! but the 09 has a great motor its like an electric motor i think its going to be a great ride. oh not sure this means anything but the old carb cannot be rotated on the bike for jet changes ,the 09 carb can !! gasgas forever!! thanks for a great site
ferguscawley
New member
The metal spigot between this new carb and the reed block is different (ie longer) than the one used with the older carburettor. Of course, the GG manual does not reflect this so be careful if ordering one.
My experience of these carbs is that they need to be jetted considerably leaner than the regular PWK 38 carb. On the 300 it meant going from a 178 main to a 172.
My experience of these carbs is that they need to be jetted considerably leaner than the regular PWK 38 carb. On the 300 it meant going from a 178 main to a 172.
