pumper carb or jet kit.

i bought a 01 klx 300 last year to get back into dirtbikes. i am looking for ways to improve the bike, with a little more performance. i have done the free mods, but want something a little more. i have be thinking about buying used pumper off of ebay and making it work, or just a jet kit for now. then there is always the possibility of a big bore kit later. if i take the cheap road and just buy a jet kit now, will i just have to buy a pumper later if go to a big bore kit.

and is there a common mxer that guys are gettting used pumpers off of?


I have a 331, with a jet kit (132 main, 40 Pilot), on the stock carb. It seems great to me. I hear those with a Pumper rave about them....sure seems like a good idea, even if it isn't necessary. If you ride great changes in elevation, the stock CV Carb might be a bit more friendly...

Bill Blue tweaks a pumper carb that is plug and play for this bike. Search for B and B Cycle Restorations for his email address. He's the gentleman that produced my 331 Big Bore, and he makes up to a 351.

been leaning towards the pumper. been keeping an eye one fleay bay and some other sites. likely go with the MIKUNI 36MM. what jetting are ppl running. i am fairly close to sea leavel and never over 2000feet

The throttle response on a pumper is much quicker than a CV carb. More like instant lift rather than twist and wait for something to happen. I have a TM 33-8012 that was bored to 35mm and it seems to work very well.

On my son's old bike, I put a TM 33-8012 without boring it, and the primary difference is that the bored carb has more mid range power, but the stock pumper has better low end power.

If I recall the one Bill Blue modifies is 34mm which may be the best of both worlds. Just make sure that if you do buy a used carb that the slide is not wore out...

To get out riding and having a blast Right now I would say Get the Dyno Jet kit and a New bigger Header Pipe... you've done the free Mods. You will need the header pipe no matter what you do. stock CV carb or Pumper Carb.. I rode for 3 years on my bike with the free mods, Header pipe, and Dyno jet kit and loved it... bike never let me down and still had the power to make me smile .... Last year I installed a FCR 37mm Pumper.... It took alot of work getting it dialed in but i am very happy with the out come... Guess what im saying is.. for the cost of a Dyno Jet kit you can be out having a blast and decide later if you want to go though the pains of getting your pumper carb installed.

thanks for the input. what header pipe are you guys using?

I have pretty much followed js2nelson except going to the FCR carb. Our group rides high elevation from time to time and they have a devil of a time getting them dialed in. However I am probably going to install the 331 or 351 kit if I can get past the vibration issue and possible heat issue. If I do I will stay with the kitted CVK carb in the beginning.

if I do not like the performance I will opt for Bill Blues mikuni.

Have you had issues with vibration or heat ?

agree 100%. jet it.When you are bored w/ it, get the BB 34.

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