Like all of us on here, sooner or later we've gotta mess with carbs (because the factory runs them so darn lean). My question is: Is it worth the money to mess with the CV carb (if that's what these are on my '09) or am I better off trying to locate a pumper carb? Are pumper carbs stock on other motor bikes or are they over the counter only? I'm assuming there are different mm's for the pumper carbs, so what size would you want? And why are pumper carbs so much better than the CV's?
As much input as I can get would be great!

 

Not totally true. AUS and NZ bikes are jetted fine from the factory. #132 main and #35 pilot with no cap on the fuel screw.

CV carb' works fine for dual sport. Mine runs really well now its set up.

 

My bike was fitted with FCR pumper by previous owner. My GF's bike has the stock CV carb. Here is why "I" like the FCR on my bike.
1. No choke starts every time.
2. Seems like instant throttle response.
3. Idle to full throttle with less twisting of the wrist.

What I dont like about the pumper carb
1. I think my carb is a bit leen at 1/8th to 1/4th throttle. I am hesitent to open it up and fark with it becuase I am not sure I fully grasp what to change or where to get the parts, although I have googled and googled and found a few articles and tips on tuneing it. On the other hand there must be dozens of threads on how to tune the CV carb on this forum alone. When the GF says she is ready for more power I allready feel confident that the dynajet kit and the good threads on this forum will help me sort it out.
2. The cost.

analysis if and when I replace this KLX I will be getting a pumper

 

I guess my reason for wondering which carb is the better one, is because I've had to work on a friends CRF250 and the throttle response out of this bike was phenomenal. Now I totally understand that it is a race prepped engine, but we are still running the same CC's. I also understand the short stroke of the CRF gives it that quick response. In my opinion, I can see the plus and negatives of both. I feel with a CV carb it's very forgiving in having flat spots due to engine vacuum determining how fast the slide comes up.
The pumper carb, I can see you must have precise tuning, being you run the slides. If you open them faster than what the motor is capable of taking in air, you end up with a bog. So getting the correct mm is very important.

No one has answered my question, do you pull these off other bikes or buy them over the counter?

As for me, I'll keep my CV for now.

 

I belive most buy them aftermarket but
Here is a quote from Thumper Talk

 

If you don't want to spend the big bucks and want to make it easy to deal with the lean jetting without tearing down the carb several times, consider the Dial-A-Jet fuel adder by Thunder Products. I've run one on my KLX650 for over ten years, having it compensate for the stock lean jetting, the addition of a big bore Vulcan piston, a full reverse cone megaphone exhaust, an opened up air box lid, altitude changes from sea level to about 5000 feet, and temperature variations from 18-95 degrees F. I was familiar with the product before, back in the 80s when I was selling bikes and had a Nighthawk S with the midrange flat spot. The DAJ took care of that and took care of my KLX. My friend put one on his XT225 with excellent results too.

It's easier and less time than jetting. It works much like Mikuni's own PowerJet, supplying additional fuel mix when the intake draws a vacuum due to leanness. If you understand fluid dynamics, it just makes sense.

The ATV and snowmobile people have taken to it like crazy, but the motorcycle people lag behind. I figure it's due to all the old timers and their influence, using hard fixed jetting like always. Both Dirt Bike! and Motorcyclist did tests of the product, which is reprinted on Thunder Products' web site, bot giving positive remarks about it. Motorcyclist even mentions dyno testing on a GSXR showing gains. Then there are all the ATV and Snowmobile magazine articles and the individual testimonials.

You can call and talk with them, very friendly and helpful. I have. We also talked about the lack of use in motorcycles. The guy at Thunder Products told me they've not heard any negative comments from any user who did the installation as the say. I've not had anyone who's bought one on my recommendation say anything but positives on it either. The negatives come from those who haven't used the Dial-A-Jet and decided it can't work. All I can say is I'm glad I read the tests back in the 80s and used them then. I've never had my carb down for jetting in over 10 years and 43,000 miles, yet have modified the engine and run in varying atmospheric conditions without any glitches.

Check them out and see. I'll probably do another one on my SR500 street/tracker when I'm done with it.