The 650 Dakar Thread

Discussion in 'Thumpers' started by underwaterguru, Mar 10, 2009.

  1. eakins

    eakins Butler Maps

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    Good ? there. No idea?
    Might be they expect a rebuild on a regular basis vs trying to keep an oem shock alive for as long as possible.

    I'm going to figure out a guard solution one way or another if no one here has one.
  2. NahdarVebb

    NahdarVebb Lukas

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    Well that sucks, i put hopes into the sock because I hoped I could postpone solving my oily motor problem. Like getting two years extra :lol3 I am mister Procrastinator.
  3. Burner25

    Burner25 Adventurer

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    Ok got the tyres
    Serviced the bike
    All bearings are good
    Got progressive’s for front on order, and rear will be done.
    Is a better exhaust a must?
    Anything else I’ve missed?
  4. Gravel Seeker

    Gravel Seeker Old, growing older.

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    you won't pack a good shock unless you are riding on motocross tracks (or possibly Australian corrugations hundreds of kilometers on washboard gravel roads)
    = wrap it and forget about it.
    No, but seriously just put the sock on and ride it. IF you ever notice bad performance you know what to do about it.

    No. But it sounds better and drowns out the intake noise.
    Also, with a single can, you free up space to carry tools or more fuel....or something else you can mount in its place.
    eakins and NahdarVebb like this.
  5. NahdarVebb

    NahdarVebb Lukas

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    Intake noise :hmmmmm

    Yesterday I watched a guy who cut holes into intake and finally heard that it really, even on the camera, makes some change. Something I couldn't grasp for a long time. But that a standard untouched intake make a noise. Since you ride with earbuds...I never noticed, it's dangerous act to not ride with earbuds. One can hear strange things. Blissful ignorance.

    You checked/changed all of them? I looked up bearings needed for a swingarm and linkage end and boy.
  6. Gravel Seeker

    Gravel Seeker Old, growing older.

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    Pretty sure it's the stock intake that makes it sound like a sewing machine - not the exhaust. I use ear plugs if I'm riding longer than 5 minutes or faster than 80km/h (if I'm going on the highway).
  7. velo-hobo

    velo-hobo *_*

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    Is there any downside (performance or otherwise) to modifying the intake? I see references to this a lot. I'm not planning on changing my stock exhaust which is in good shape anyhow - sure it is heavy and takes up space but I don't mind the sound and kind of prefer it to be quieter. All the aftermarket stuff seems like it would be louder (no offense to those who do like loud pipes - let those who ride decide! but for me it's not music to my ears)

    With the intake opened up, is a different air filter necessary/recommended?

    Apologies if this has already been covered ad nauseum, I'm feeling lazy with my web browsing today
  8. NahdarVebb

    NahdarVebb Lukas

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    Re noisy mufflers: had the same opinion. Didn't have problem with it sound, likes how "silent" it was and didn't mind it's weight. Until I had to take it off for a moment. Then I realised how much it actualy weighs. Since I ride offroad more than I used to when I bought my bike, and I am not a pro nor do I have skills, I believe some weight saving will do me good. Sadly, with more noise as a tradeoff.

    Re intake: Not sure whether cutting in some holes into sides of the intake make any difference other than sound but taking it whole off might. Toby swears that with this engine power output, taking off whole airbox and so the intake, there's very little difference. But thinking it through more, one has to come to a conclusion that any kind of an airbox has to be installed. Since it needs dense cold air that is nonexistent around throttle body, outside possibly less warm air is needed - hence intake.

    I guess there is more thought put to it.

    On the other hand there is a guy who claims he worked on a dyno and was offering his insight in cold air intakes people do in cars and he said that it makes virtually no difference at all in comparison to stock, already thought thru airboxes. That it might help but under certain circumstances and not all the time for what people install them in first place. I believe cold air is needed but riding in 30°C warm summer day won't help. Will the sped up air through intake lose some heat in the process? Where would the warmth go since there is no heat exchanger...
  9. velo-hobo

    velo-hobo *_*

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    Cool - yeah the extra weight is only a minor thing for me - I almost never ride without hard cases stocked with tools/spares, usually keep the gas tank topped up, has engine and fairing guards, and on longer trips have about a gallon of water and a six pack on board, but my camping kit is backpacking-light, so there's a balance there.

    I had all the bags off at a campground recently though and had to move the bike at one point to make way for a car - so much easier to lift off the stand without all my crap on it! :hmmmmm

    But getting things lighter for the type of riding I do (mostly paved roads, bad pavement, gravel) seems like a rabbit hole plus $$$. To even get to substantial areas of chunky dirt I have to ride hours on pavement at 50-75mph.

    So only when it comes time to replace things will I consider lowering the weight where possible. I can pick it up by myself loaded up with gear so there's that...

    Seems like the intake mod is more about personal preference for the sound and trying to accumulate marginal performance gains? The bike has plenty of power for me already and sounds fine to my ears.
  10. Don Coyote

    Don Coyote Long timer

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    Did you try (succeed?) to remove the plugs with the airbox still on?

    Be careful with those, I was working with distractions around last year and managed to cross-thread the outer one even working with the box off. Took over an hour of us messing with it to get it to go back in satisfactorily. I was so worried I put the beer aside until we were done...
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  11. WayneC

    WayneC Long timer

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    Yes, you can knock out low end performance, you also open up the problem of water to the air filter along with increasing the temp of air into the intake
  12. eakins

    eakins Butler Maps

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    Good ?
    I just bought a Uni filter and I'm wondering if and how I should mod my intake.

    I'm happy with my GPR muffler.
    Less weight for sure and the motor revs better.
  13. eakins

    eakins Butler Maps

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    So only cut minimally on the intake, inside edge, and drill a drain hole on the low side.
  14. Burner25

    Burner25 Adventurer

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    Yes I changed both with the air box on, and it took ages, the plugs were quite new so didn’t need to be done, so it was pointless! But there’s got to be an easier way, there’s no room at all!
  15. Burner25

    Burner25 Adventurer

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    When changing the air filter I noticed a bit of oily water in one corner after the filter, is this were a drain hole is needed?
  16. WayneC

    WayneC Long timer

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    No but water has come through the filter into the airbox, see here, drain hole is to stop water build up outside the filter, can saturate paper filters
  17. Gravel Seeker

    Gravel Seeker Old, growing older.

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    How about trying it without modifying the snorkel first and then, if you feel it's anemic go ahead and drill it.

    EDIT: Don't cut holes meant to increase airflow after the air intake temp sensor. Read next post for explanation.
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  18. Gravel Seeker

    Gravel Seeker Old, growing older.

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    Not going to diss your guy, but maybe he shouldn't have been tuning engines?

    "Everone" knows that an engine runs better in cool air or right after you start it.
    Also why F1 and rally cars lost 20-25% engine power when racing in Mexico at high elevation (F1 now is close to what it is a sea level with hyper modern turbo technology).

    Ever wondered why turbo cars have intercoolers? The process of compressing the air creates friction which creates heat that raise the temperatur of the air, making it less dense and the effect of the turbo is less.


    Warm air is less dense

    As AIT climb in your motor you will notice that you will be losing power. This is because air expands as it heats up, therefore there will be less oxygen molecules per cubic inch. So even though your motor is going through the same stroke of displacement, and the motor sucks in the same amount of volume of air, that doesn’t mean that the volume of air contains the same amount of oxygen molecules. Because of this the car will have less power as the AIT’s get hotter. This is why people install hood scopes or intakes that bring in cool outside air instead of sucking in warm air from under the hood. Also you will notice that the A/F ratio will become richer because while the same amount of fuel is being injected, yet the air is not as dense as it was because of the warmer air temperature.


    Cool air is more dense

    Cooler air gives you more power because there are more oxygen molecules per square inch of air….meaning the air is denser. Denser air is better because your motor will now ingest more air in a given stroke. Because of this you will notice that the A/F ratio of the motor will become lean due to that fact that your motor is still injecting the same amount of fuel but there is more oxygen present because of the denser air.


    http://www.enginebasics.com/EFI Tuning/Air Intake Temp Tuning.html
  19. NahdarVebb

    NahdarVebb Lukas

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    Ehm, but like I wrote something different and as I am aware he did not say anything different either.

    Nobody negates physics.

    Only, that cold air intake kits people install into their cars in hope of getting few more hp is useless. Those stock intakes, in other words airboxes, draw "cold" air from outside of engine compartment already (ie outside car), those are also sealed from hot air inside engine compartment (ie there is physical barrier). The only disadvantage stock airboxes have is the fact that the tubing is made of plastic and a non cleanable paper filter is installed, whereas aftermarket cai include fancy composite or aluminum tubing and hiflow filter. That's that. You're shy of 300+ usd and end up with same performance.

    A friend of mine has a saying about it which I completely agree with: "If I take a dump in the morning, I'll make more hp by doing that than what cai gives me".

    I was talking about modern-ish cars. Maybe older one draw air from inside engine compartment, don't know.

    When I get home from work, I'll look up that video and you can examine yourself what he did or did not say.

  20. Gravel Seeker

    Gravel Seeker Old, growing older.

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    Relax, I was replying to what you said - not what you meant....
    "there is a guy who claims he worked on a dyno and was offering his insight in cold air intakes people do in cars and he said that it makes virtually no difference at all in comparison to stock"
    Data out is only as good as data in.
    Had you mentioned budget kits, I wouldn't have commented, but read it as you meant high end engine tuning.

    Since we're on the subject, driling holes in the snorkel is probably less effective than a morning constitutional, but I'm not an engineer so drill away.