KLR650 + Pumper Carb?

Discussion in 'Thumpers' started by juames, Jun 27, 2011.

  1. juames

    juames Have Fun, Don't Die!

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    Anyone ever put a pumper carb on a KLR and is it worth it?:ear
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  2. MotoBoss

    MotoBoss Bad Influence

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    I haven't. I would be interested in knowing also. Gonna do a 685 kit this winter and if a pumper makes a differance it would be good to know.

    Good question.
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  3. Kawidad

    Kawidad Long timer

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    I'd be interested in that too. However, my personal experience with a Suzuki DR350 is that it's overrated. I was told about the magical transformation of the bike with the different carb (cv to pumper). I did it and not doubt it was better, but magical no. In fact, I'm not sure it was worth the money.

    But, having written that, I'm definitely open to this idea on the KLR.:ear
    #3
  4. FatChance

    FatChance Road Captain

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    Too expensive for a KLR! :nod




    :lol3
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  5. BikePilot

    BikePilot Long timer

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    I'm fairly certain it will add a lot of throttle response and prevent the carb from shutting down on really hard impacts. Probably limited utility on the road, but perhaps helpful in the dirt if you like to snap the front end up quickly on just throttle. I had a pumper on my DR350 and, unlike an above poster, thought it made a tremendous difference. I also have one on my XR650R that works quite well. For street/dirt road use it probably isn't worth it.
    #5
  6. Beezer

    Beezer Long timer

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    I saw a thread about that a couple years ago somewhere... prolly on dot net. The Hardleys use a CV 40 on (I think) the Sportster. The casting is a bit different because of the air filter. They are around as a take off due to "upgrades". I saw one in a junk store & considered it, but didn't make the leap. The down side is it would kill the fuel mileage no doubt, and I finally decided it wasn't worth it to me. The 685 & some head work, an exhaust system & carb kit does pretty good.... :evil
    #6
  7. peter650

    peter650 Been here awhile

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    On late model klrs i think the flywheel is to heavy.I think for a pumper carb to do it's thing on a klr, you would have to sort out the fly wheel.Early model fly wheels are lighter.Instead of Kawasaki giving us more grunt over the years,they just gave us a heavy fly wheel.A cheap trick to make you think you got more torque than you do.
    #7
  8. ER70S-2

    ER70S-2 Long timer

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    :rofl :freaky
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  9. GSequoia

    GSequoia Where are my tools?

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    So you're saying we need to rig a squirt gun full of gas with a cable wrapped around the trigger and just squirt it in when we need the oomph?
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  10. juames

    juames Have Fun, Don't Die!

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  11. Kawidad

    Kawidad Long timer

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    Yes, that might be the hot ticket. :1drink

    Or, ................ :deal I don't why anybody with a milling or CNC machine hasn't made an adapter for the CV40 carb that were standard on the HD bikes. Those already have a pumper installed and should be really close to the jetting used on the CVK40 that is the original carb. I wish I had one, I'd do it, but since I don't.......................
    #11
  12. danketchpel

    danketchpel Long timer

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    This issue has been visited on some other forums. The problem is clearance, there is very little above the carb.

    I have been looking at the HSR40 which is the pumper replacement for the CVK40 carb meant for Harleys, but hey, it's still a decent pumper carb.

    [​IMG]
    #12
  13. XDragRacer

    XDragRacer Long timer

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    A pumper carb should surely improve throttle response on a KLR650; no longer suffering the inconvenient delay while the CV carburetor develops vacuum necessary for lifting the slide and needle . . .

    Clearly, an accelerator pump offers an advantage in the motocross, hare scrambles, and flat-track competitions, should KLR650's enter such races.

    A pumper doubtless offers competitive edge over the CV-only carbed machines in wheel-to-wheel racing.

    Invoking an accelerator pump appears to me a modification justifiable perhaps in competition. Ordinary KLR650 service life spectrum? Not so much, I think, but--YMMV!

    Now, if we could simply just bolt on an ex-Harley CV40 . . . why not?
    #13
  14. Some Dude

    Some Dude what attitude problem???

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    what he said :lol3
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  15. Kawidad

    Kawidad Long timer

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    Details?????????????? :evil:evil:ear



    It's not just a question of racing or competition, it's also a question of drive/rideability. Several things hold back the KLR in the mind of more aggressive riders or riders who do more challenging off road work. One of those things is the instant power to clear obstacles and that power comes from an accelerator pump (among other factors too, of course)

    You can't bolt a HD CV40 because the intake is different. The CVK slips onto a rubber boot that is bolted to the cylinder head, the CV bolts directly onto an aluminum Y pipe. I also believe that there are clearance issues as stated above, but I believe those clearance issues are related to the throttle cable wheel.

    Besides almost every other bike out there has performance stuff, why not us?:deal
    #15
  16. XDragRacer

    XDragRacer Long timer

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    Hey, go for it, Kawidad, if removing some milliseconds of delay between throttle opening and slide elevation is worth it to you!

    The accelerator pump merely dumps raw fuel into the carburetor venturi upon throttle opening, preventing a fuel-lean condition at the slide-opening instant; the CV carburetor opens the slide when intake air velocity produces sufficent vacuum, concurrently supplying an acceptable air/fuel mix to the engine . . . KLRistas typically enhance throttle response by hogging out the slide vacuum port (to 7/64" diameter).

    What is the MSRP (Manufactuer's Suggested Retail Price) of a typical 40 mm pumper slide carb these days? [Answering my own question, I found for $ 289.95 on the Web, "40mm MIKUNI TM Flat Slide smoothbore Pumper carburetor TM40/6 with accelerator pump for 4-stroke use." ]

    Regardless, if your riding style profits sufficiently from implanting a pumper carb, as mentioned, go for it!
    #16
  17. Chazangie

    Chazangie KLR665X

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    Gotta chime in and try to bring this thread back to life. I have installed a Harley pumper as well as a Mikuni TM38 non pumper. Both Carbs suck. What I have:
    92 KLR650 punched to 665 with 101mm Wossner piston (amazing) LA sleeve, p&p head, intake and exhaust ground and matched to the head, airbox mod, White bros E2 exhaust. Stock header
    They weren't very good on what they came on for that matter.
    Here's the skinny and fat:
    Harley pumper
    40 pilot
    150 main
    883 needle
    Had to modify the pull pull throttle cable and Harley cable mounts on the carb
    custom intake adapter(filter side) and modified intake hose.
    Hang up: The Harley CV needle jet diam is larger in the seat. The CVK needle jet just drops through the whole thus forcing me to use Harley jet needle, needle jet, and emulsion tube.
    Conclusion:
    No enricher= always gonna pop on decel like a Harley. After trying several main jet combos and hours of tuning the ac pump with shims, I was unable to get it right. Yield=more fuel burned, engine pops on decel. My fully worked CVK was better.
    PM for pics.
    I will do a write up on the TM tonight
    #17
  18. hayduke.klr07

    hayduke.klr07 Been here awhile

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    I know nothing of a pumper carb but.....

    Was just in Moab and made the obligatory stop to Arrowhead. Fred is working on supplying a plug and play carb. It is a Mikuni performance carb. The way it was explained to me is that the stock carb/diaphragm works on a vacuum. You need rpms for vacuum which reduces throttle response. Seems like something I want to do to my moto. Problem is I just got my hands on an xt225 which is taking my attention right now.

    I saw this carb and talked to Fred about just a couple of weeks ago. Thought I would share the info.
    #18
  19. SkiBumBrian

    SkiBumBrian DualSport Crazy !!

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    I run a 44mm Lectron PowerJet. Took me mega times tank on and off to get the metering rod right, carb is cold blooded but overall awesome performance. No need for anything but the CVK unless extensive headwork and BB done....
    #19
  20. tom c

    tom c Not again....

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    I rode a buddys' DR650 this weekend - he had installed a pumper carb and found that it improved throttle response. Indeed his DR seemed more responsive than my KLR650.

    per Chazanies earlier post - Arrowhead Motorsports in Moab is now making the Mikuni Performance Carb Replacement Kit - $265.95.

    http://www.angelfire.com/ut/moab/klr_fuel_air.html

    Has anybody out there done this to their KLR?
    #20