Mellow out the 990?

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by txbear55, Oct 22, 2012.

  1. txbear55

    txbear55 Been here awhile

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    I guess a question for the engineers....CJ? Has anyone considered modifying to a heavier flywheel to mellow out this rip snorting beast? Back in my enduro days Moose Racing had a mod to a heavier flywheel for the motocross bikes. It smoothed out the power delivery, esp. when you came "on the pipe". Seems like it would sure make the 990 more controllable in technical sections. Thoughts?
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  2. Qwik

    Qwik Adrenaline Addict

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    Much easier to just go down one tooth up front. These are sedate machines at partial throttle
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  3. geometrician

    geometrician let's keep going...

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    You aren't going to be adding any weight to the 9x0 Lc8's flywheel/rotor w/o lots of work. And you're not adding anything to the crankshaft itself unless you're in the crankshaft business

    2-strokes have a different arrangement that allow you to add a balanced disc to the outside of the ignition/charging flywheel. LC8's don't share this arrangement at all...
    [​IMG]

    Perhaps a G2 throttle cam w/changeable profiles will help with throttle control.

    If the bike is too peaky for your liking then go UP (not down) a tooth on the front sprocket- going down allows the engine to rev up faster while adding a tooth does the opposite.

    Just put her in 3rd gear & lug it to keep from breaking the rear tire loose
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  4. Martynho

    Martynho No more Chilegringo.

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    The engine is not the issue in the technical stuff, its the weight of the damn thing :huh. Like the man said, to tame the engine just lug the engine a bit.

    Having said that the main solution to all your ills in the rough stuff is to do just the opposite, keep focused on where you`re going a long way out, keep her spinning up and point her in the right direction. She will take care of the rest

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  5. geometrician

    geometrician let's keep going...

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    +1.

    She's a beast to get used to in slow stuff, but have faith in the chassis & she'll amaze you what she can do. There were a few moments when I was new to her I thought I was in trouble but I just kept her pointed where I wanted to go and she had no problems... once you get used to the bikes performance envelope & abilities you'll understand why the Orange Koolaid is so tasty for us!

    [​IMG]
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  6. txbear55

    txbear55 Been here awhile

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    Just brain stormin'....Monday morning and all! Thanks for the thoughts!
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  7. snowhawk jockey

    snowhawk jockey Slack Jaw Gaper

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    As mentioned earlier, old school Moto dudes (and those on a budget) ran taller gearing to keep the wheel from spinning up, in low traction conditions. Keeping the RPM down meant they didn't get on the pipe until they were well out of the hole in the corner, keeping the drive on the ground instead of spinning it into the air.

    Your 950 will do the same thing, just with an upshift. Riding a gear high and staying smooth on the throttle, lets the momentum take over. This momentum is what will carry the weight of the bike through/over the obstacle.
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  8. zen rider

    zen rider veteran rider

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    I did put on a g2 throttle cam (400 SIZE) to soften the first 25% of the throttle opening as it was jerky at very low RPM. While this was really a fueling issue, the throttle cam softens the problem acceptably.

    I added a Steahly flywheel weight to my two stroke KTM 300XC to mellow and add traction. As another person stated this is simple and cheap on a 2T. Not as common as it once was though.
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  9. Black Hills

    Black Hills Long timer

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    I was able to get decent results with the powervalve adjustment/springs on the 300, did iyou try that as well?
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  10. DuctTape

    DuctTape Been here awhile

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    Rekluse!

    You spend more time riding and less time fighting her which adds a lot of miles to your ride since you're not nearly as tired at the end of the day.
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  11. geometrician

    geometrician let's keep going...

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    Once the Rekluse engages it's still the same engine you're dealing with.

    Auto-clutches save your left forearm from abuse & offer better starts on hills if you stop- but it's still power/gear selection in the end. Plus you lose closed- throttle engine braking when the RPMs drop below engagement point, as well as the ability to bump-start the bike
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  12. robdogg

    robdogg turnip truck driver

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    good point.. but I guess it really depends on what the OP is really after. An autoclutch does wonders in tight technical stuff as it makes your beast nearly stall proof. I find that most people have trouble maintaining good throttle/clutch control when the going gets rough.. like riding along a rocky section, up on the pegs, and your front wheel hits a boulder and instead of feathering the clutch a little and blipping the throttle, your reaction is to pull the clutch in all the way and you kill your momentum, and the motor stalls, and the next thing you know, your dropping your mammoth steed on the rock tops. So if that's the concern for the OP, an autoclutch, and maybe smaller CS would definitely help IMO.. I wouldn't waste money on a G2 throttle tube.. those are useful on an explosive small bore two stroke, but IMO, the big KTM twin spins up rather slowly already.. heh

    Personally tho, I'd ride it like it is, and just give it a lot more seat time.. and something some folks rarely do, practice practice and practice.. even in flat space like a parking lot.. do some slow speed drills.. they will work wonders on your confidence in handling and throttle/clutch control

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  13. FakeName

    FakeName Wile E Coyote SuperGenius

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    This is not completely true.

    I rarely lose engine braking- I have to be close to a standstill- really- like falling-over slow. And in anticipation of installing on a 990, I asked Rekluse about the no-bump-start idea.

    While true on my 525, it won't be on a 990. The Rekluse 990 uses a replacement clutch slave that has the adjustment the Rekluse requires. On the 990, it's easy (like turning an allen screw easy) to return the clutch to manual performance, providing bump-start capability.
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  14. DuctTape

    DuctTape Been here awhile

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    I disagree, you are able to go a lot slower then a stock 990 with greater control even in 2nd gear and as for the deceleration all you need to do is blip the throttle and she engages and slows you down. As for bump starting you are able to bump start the newer Rekluse.

    I say this from experience and not from something I've read.

    I too thought "I don't need no stinkin Auto Clutch" but now that I have one I can go places I couldn't before. Find someone that has the newer version and take it for a spin, you'll be impressed with the transformation.
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  15. tahoeacr

    tahoeacr Long timer

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    You could always unplug the octane wire and run 87 octane gas. Depends on the A/F map. Some say it makes things worse. On some bikes it just takes the edge off. It's free, so worth a try.
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  16. Zuber

    Zuber Zoob

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    I never use the low octane fuel (LOF) switch. Tried it, didn't see much of a difference. Its effect is mostly above 25% throttle opening, much more throttle than I use when off-road.

    You could use TuneECU to retard the timing, esp. in the low throttle/low rpm. It should give you more control and less snap. But, it would reduce the fuel mileage and power too.

    I've had an idea for a while to create two power settings. Use the LOF ignition map to create this 'soft throttle' setting using TuneECU. Then put a switch on the handlebars to control which map to use. The LOF map for off-road and the normal map for on-road mileage and aggressive situations.
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  17. snowhawk jockey

    snowhawk jockey Slack Jaw Gaper

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    Good call! I forgot about that as it was the first thing I did to mellow the lurchy throttle while offroad. That butters up the throttle a bit for sure.
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  18. tahoeacr

    tahoeacr Long timer

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    Sort of what I had in mind. Just never have enough time on the dyno to finish it. Advancing the timing on the regular map for my elevation. Then switch the standard maps into the LOF map so when I go to sea level I can have no worries.
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  19. cat

    cat Long timer

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    :norton How does it work? The LOF switch, a switch in the ECU, set by TuneECU - or the KTM diagnostic tool - to switch the ECU to use this LOF ignition map, an alternative ignition map??
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  20. tahoeacr

    tahoeacr Long timer

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    There is a wire under the front of the seat. Forgot the colors. Someone will chime in and tell you. Just unplug it. It's pretty common in FI ECU's these days. When the ECU comes on it looks for a ground. If the wire isn't grounded then it reverts back to a different map. The 990 map is just reduced ignition timing for Low Octane Fuel. As if you were going somewhere and only 86 octane was available.
    #20