250-500cc carb swap....which carb

posted this in gasgasrider.org also....


I believe my 2010 gasgas ec300 came stock with a Keihin AS2, The float bowl is shallow, the side of the carb says PWK, and the top has two screws that hold the spring and slide mechanisim in. Now here is my problem.... Said carb is now on my 12 husky wr300 because the mikuni it came with i didnt get along with. so gasser needs new carb or husky needs new carb depending hoe you look at it.... The only carb i can find seems to be a regular PWK airstriker (deeper bowl, round plastic screw cap holding the spring/access to needle)... What are the differences between these carbs? Which one will perform better where. The husky is my faster, open flowing trails and dune bike, the gas gas is my single track go to bike. Should i continue to look for an AS2 or just buy the air striker carb? anyone have any experience with BOTH? Help please and thank you!

I would try to fix the issues with mikuni and put it back on husky. ie try carb divider mod, or different needle etc . I am not sure if I would recommend the pwk as it can give lean bog and may lose some top end

The PWK is WAAAY better on the 250/300. Motosportz sells 'em with jets and it will make your bike run so much cleaner you won't believe it......gas mileage goes way up too....17 to 21mpg in tight woods for me. I never have to touch the fuel screw either.

On the 125 the Mikuni puts out more brute power but you will never miss it on the 300.

I have a pwk on my 300 and it runs good. I never ran the Mikuni though to compare. I herd the PWK would be better for the huge elevation changes I ride in a day. Start at 4500ft and go up to 10000ft in one ride type of stuff. I was told the Mikuni would not tune well for that much elevation change. R&B can put a divider plate and other mods that help the Mikuni just not sure if it would help for the drastic elevation / temperature change.
Just a idea, Use the Mikuni in the bike that stays in more of the same environment?
And the PWK in the bike that see's different environments all the time?

If you are happy with it why not just get another GasGas carb?

The main difference between a PWK and a PWM are the slide shape. The PWK uses an oval slide and the PWM uses a "D" shape slide. Most of the current bikes that use a PWK as an OE carb are PWM style bodies with oval slides. The PWM body has the bolt on top, pilot / main jet access through the bowl drain, the shallow bowl and shorter throat.

The "D" slide and short throat tend to lend better mid to top power and the PWK's long throat and oval slide, which work better bottom to mid.

The new style OE PWK is a short throat with a oval slide, to try and get the best of both worlds.

Personally, on a bike like the 300, with tons of bottom and not as much rev, I like the PWM carb. I ran both on my 300 and 250, but for racing I think the PWM works better on both bikes.

If all I did was trail ride, then the PWK would be fine. It makes a nice, fun, grunty trail riding power, but for my style I'm liking the PWM better.

i am unable to find another carb that looks like the carb off the Gas Gas. Thats why im wondering which carb to buy...As far as the Mikuni goes i have it sold so no going back now lol. Plus im much more familiar with the keihin and having one type of carb between two bikes makes sense to me. On JD jettings website he has the PWM and the PWK air striker. The PWM is actually cheaper. Nice to here from someone on how it worked because i dont know anyone with one. So for sand dunes and faster open riding Motorhead you preferred the PWM? Like i said i have the gas gas set up for single track, and ill probably race the husky in the next race...so maybe i should look into the PWM

I really like the screw top of the PWK. The carb works and the gas mileage is very good, as mentioned.

Yeah, I'd just put the Gasser carb back on it and get a PWM for the Husky.

both carbs (pwk with screw top cap and pwm) fit in place of stck mikuni with no problem? The airstriker 2 did no problem but i have read its a touch smaller then the PWK with screw on cap. Not sure where the PWM is size wize

PWM should be very close to your gasser carb. The PWK is longer than the stocker, which some gripe about.