I did some searching but really found mixed opinions post pumper carb. What can I expect? I hear the term better throttle response being thrown around but my bike already has great throttle response in my opinion.



klx 351
airbox lid removed
HMF slip on, stock header
128 dyno, 38 pilot, needle 4th clip down
14/42(stock) gearing

 

You can expect to spend more money with marginal gains at best. I dont want to knock anyone. However, I think the folks that put a pumper on their KLX, and then rode it, and reported the bike all of a sudden was like riding on a raped ape, experienced expectation syndrome.

They expected the bike to act a certain way and fooled their minds into thinking it achieved their expectation. Without getting scientific data( a dyno) to prove their hypothesis. I did not get a dyno either, but I felt there was no reason to, as it did not do anything for me but decrease my fuel mileage by 25% or so, and gave me limited improvement off the line.

There was no wheelie mania, no trouncing on and beating my buddies KTM 450exec, I not even sure If I could have beat the DRZ400. Peronsally unless your going to dyno the bike to dial in the fuel ratio, you realy are not going to get 400.00 worth of performance. You want to get better performance? Upgrade the suspension, get better wheels that are lighter and stronger, nicer handle bars that make you more comfortable, put some good Dust Busters or some other hand protection to keep you from breaking your hand, and controls when you crash. I think your sig said you already had the 351 right?

As an FYI,

I had the pumper on my klx both before and after I increased it using the klx300 upgrade. I did not see any massive improvement so i sold it about 2months after i bought it and went back to the stock carb with the dynojet kit.

Maybe my fatass restricted the bike from being what it should have been. The biggest difference that I saw was my wallet lost more weight than I did.

Take it for what it is worth as it is omho.

 

jhoffy,

You can expect weeks of dialing it in.. messing with it, taking it apart many many times.. a jerky response.. sprained back from the jerky throttle response. doctor's visits for your back, and spending money on various jets.. throwing it into the box and putting your stock carb back on.. etc etc.. its been a long time and I have considered just putting the stock carb back because it is so reliable and smooth ..

 

I was fortunate to have a pumper dialed in and installed on my bike when I bought it used. The thing I like about it more than anything else is I can start my bike every time without messing with a choke. Thats the way a bike should work!

 

The throttle response and the immediate power is what I wanted the fcr 35 carb for. I didn't mind the loss in mpg, as the bike is way more fun to blip the throttle and be able to bring the front end up. But everyone has their expectations and mine were met with the pumper carb... to each his own. Weeks of dialing in... come on.... Bill sets his carbs up for your area to start off with...

Good luck

 

Yeah, I am with you - I don't see the gains being worth the cash. My CV carb and 351 are like a dream. Instant response. I'll pass on that, spend the money on your suspension.

 

I have a big problem with the stock CV carb. The slide gets hung up in the UP position and then the bike wont run. I have had this issue on and off since new and am frustrated enough that i got a Mikuni. I havent installed yet but i am hoping it is reliable and after i get it jetted in, i can get back to normal. I don't know if the slide on my CV was damaged by the PO or if it is just a single bad carb but it really sucks when you are out in the middle of nowhere and you have NO throttle at all. I have found that if i tap on the side of the carb lightly with a screwdriver handle while it is idleing, it can usually get it back down and functioning. A new CV is more money than a Mikuni, so that is why i bought a pumper. I'll let you know if i threw my money away or not in a few weeks.

 

I got my 09 with the stock carb jetted, power bomb~Q4, and no air box lid. Good running little bike[XL 125ish]. I got two front flats because I couldn't get the front tire off the ground. A few miles[about 1500] and a BB carb and it would damn near wheelie in first enough to clear some little logs. 4600 miles and a 351 kit now it it a bit better. The KLX 250/351 is a great bike altho it is heavy under sprung and still slow.

Ride a 520/525[there 510s] if you want a pumper hit.

Rag away.

 

huh, never had that happen.. Have you opened it up and made sure all was well inside? No gunk? Clean? Spring good?

 

I really have to look into upgrading my suspension. I weigh about 190lbs. How far off of stock suspension am I?