The KTM300 Thread

Discussion in 'Thumpers' started by GasGas300, Jan 11, 2010.

  1. greasyfatman

    greasyfatman Long timer

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    Any one run a throttle tamer? If so recommendations?
    I have had this bike fly out from under me on a few double log crossing. I think I could benefit from slower initial opening.

    “ I looked back and greasy’s bike was coming at me skid plate first” quote from a rider in front of me.
    Scoutin Wyo and Bitingdog like this.
  2. Bitingdog

    Bitingdog That's not my dog

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    Have one. It helps with precise throttle control in the gnar. That and the gray wire switch really mellow it out. Also, it's a better quality piece than the stock throttle tube
  3. timeOday

    timeOday Long timer

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    This is a case where adjusting (or maladjusting) the power valve might actually make sense.

    With a reasonable choice of settings, you will just make the power hit later, but harder. That might be what you want - just never pin it.

    Or, with a weak enough spring, you will never fully open the powervalve, effectively neutering the bike.


    [​IMG]
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  4. greasyfatman

    greasyfatman Long timer

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    What one are you using?
  5. Bitingdog

    Bitingdog That's not my dog

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    G2 with the "grandpa" throttle cam
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  6. Gordy

    Gordy SUPPORTER

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    “Quick” throttles are usually not the problem. It’s usually a slow reaction with the clutch that makes it seem like a throttle problem.
    I go through this all the time with some trials riders. They want the slow (black) Domino tube when their bike comes with the faster (white) tube. The slow tubes, or cams make you twist your wrist down into an un-natural weird position when trying to give it max throttle.
    IMO and YRMV you need a standard or even a quick throttle and a quick clutch finger.
    If you slow the throttle down, you are just fooling yourself and will then not be able to open the throttle all the way and have your arm in good position at the same time.

    My new TRS trials bike even came with a modified white tube to make it quicker. They glued a wedge onto the cam and I love it!

    BCA2C117-1891-43B3-9118-52E042DE49AF.jpeg

    I would not go this extreme on the KTM but could see getting a smoother acting bearing throttle.
  7. thejrod

    thejrod Been here awhile

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    100% this. At least in my experience.
    The clutch is so much faster and more precise than the throttle for modulating power to the rear tire. It'll save you from loop-outs far better than trying to chop the throttle and waiting for the engine to spool down (takes time for all that reciprocating/rotating mass to slow - clutch is instant).
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  8. adv_sacrifice

    adv_sacrifice Been here awhile

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    I do find modulating the clutch more than the throttle to be a big help as well.

    Rich larsen (irc tire guy on yt) talks about it a lot. Clutch control is a main skill.
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  9. Bitingdog

    Bitingdog That's not my dog

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    I went to a quick turn throttle when I broke my right wrist a year and a half ago. It kept me riding (along with liberal amounts of hockey tape and ibuprofen) which was nice. However, I went back to the throttle tamer once I was all better.

    Clutch is definitely the best way to modulate traction, and prevent loopouts, but in the gnarly crap it's smoother for me to have precise throttle control too. It's not game changing one way or the other, but on balance I like it where I ride. And most of our local trails are ridden using well under half throttle 20210901_035717.jpg 20210710_214113.jpg
  10. guns_equal_freedom

    guns_equal_freedom Long timer

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    You're bass-ackwards.
    The red spring is the soft spring, the green spring is the stiff spring, the yellow spring is in-between.

    You run the red spring to get the powervalve opened ASAP, you get more power sooner.
    You run the green spring if you think that a 1979 RM125 had the perfect powerband (it opens the powervalve later)
    All they do is change when the powervalve is fully open.

    The powervalve starts to open at 5600 RPM
    With the red spring it's fully open at 7,200 RPM, with the yellow spring it's fully open at 7,900 RPM and with the green spring it's fully open at 8,400 RPM.
    By turning the carriage screw you can start opening the powervalve 150 RPM's sooner with each full turn OUT or 150 RPM's later with each full turn IN.

    No matter the color of the spring or how many turns in or out of the carriage screw, when the powervalve is fully open it's going to make the same torque and HP.
  11. timeOday

    timeOday Long timer

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    I see, so the spring resists rather than forcing the opening.

    However, if you look at the dyno I posted, it does not make the same peak HP or torque regardless in JD's testing. It appears the valve is never fully opening.
  12. Anatoli

    Anatoli Pale rider

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    BAFCD656-DB61-4DB6-B155-0910C2303357.jpeg

    Lots of 300’s racing today at Walker Valley. Note the twin horns on #375 above. Blast to pass!

    65BD608B-595B-4543-824F-B2201E5E1FCA.jpeg

    38C8BF19-E027-4E84-99C3-D422E8DA6160.jpeg
  13. guns_equal_freedom

    guns_equal_freedom Long timer

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    Look at the dyno-chart again.
    First off it's a torque chart and not a HP chart.
    Second, when did I say the powervalve is fully opened for the green spring?
    8,400 RPM
    Look at the chart at about 8,400 RPM.
    All of the torque lines are merging at about 8,600-8,700 RPM's.
    That's when the powervalve is fully open no matter what spring you are using.
    Of course the torque readings will be different for the different springs, the powervalve is not fully opened until 8,400 RPM's.

    This is the chart that shows when the powervalve is opening.
    [​IMG]

    I don't like the green spring because it kills the power until the powervalve fully opens.
    Because the engine is running at a higher RPM you get that old school "powerband" hit...BaaaaaaWWWWWAAAAAAAAAA.

    There's a lot more involved with the springs than just the colored springs.
    There's the carriage spring adjustment.
    There's the wheelie wire / map switch.
    If you're running a stock, Gnarly or Fatty (or some other) pipe.
    Do you have a high compression head?
    Are you running an aftermarket ECU?
    Did you ditch the FI for a Lectron or other aftermarket carb?
    Did you change the injector location?
    Even the throttle cam comes into play.
    Is your bike a carbed model?
  14. guns_equal_freedom

    guns_equal_freedom Long timer

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    Was it wet everywhere or was it dry under the trees?
    That's the way I like Walker.
  15. alvincullumyork

    alvincullumyork Ol Two Flags Supporter

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    I think the green spring is the hardest to ride for excactly the reason you typed. For me the red spring is the smoothest.
  16. RideFreak

    RideFreak Torque Junky

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    On my 08 I used to run the green spring in Moab, mainly because I didn't want it coming on the pipe climbing a ledge or something like that, it didn't have a head back then so a little extra throttle was needed often putting the RPMs right at the hit. Installed the head and was able to negotiate everything at a more moderate rpm also allowing me to run the red spring with less drama.
  17. Anatoli

    Anatoli Pale rider

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    It rained during the night so it was wet everywhere. The rain mostly stopped just as the riders left the start. The course was in excellent condition: everything was brushed out so you could see the multiple hazards. There were no serious injuries among those racing because of the effort made prepping the course. We had a big turnout after no race last year because of Covid. The positive energy of the crowd was amazing, everybody was really excited. It reminded me of a mini rock festival of old.
  18. Bitingdog

    Bitingdog That's not my dog

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    Sunday's dirt church ride with The Punisher. I was off my game. Never truly became one with the bike. Hadn't ridden much this summer between the heat and some remedial bike maintenance, and it showed.

    Still, it was awesome to be out. Loving the IRC VE33 Gekkota semi-gummy. Similar attributes to a Shinko 525, but a larger sweet spot. Will bang again IMG-20210912-WA0006.jpg IMG-20210912-WA0004.jpg IMG-20210912-WA0005.jpg
  19. 911

    911 Been here awhile Supporter

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    Ammo run in nh. vt.
    2 day event
    About 100 miles a day
    Not my video
    Great ride.
    There was some hard stuff not in the video
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  20. Colemanfu

    Colemanfu King of all manfu

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    Last of the summer video series. On our way home from Idaho we stopped in our favorite mountain party town. We camped up on Brush Creek, ran the skinny, and threw down in town. Fun way to end the summer.

    Turned out to be one of the most visually pleasing trails of the entire 7 weeks traveling :clap