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Discussion in 'Canadian Daves JustKDX' started by motopsycho87, Mar 26, 2012.

  1. motopsycho87

    motopsycho87 Rookie DRN Member

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    ... but, I just had a 'brilliant' idea.



    So, the cooling system, when it over pressurises, it squirts into that tank at the back, there is no way it can suck it back in (look at the design if you don't believe me).

    Anyway, my bike always has a bloody puddle under it from the gearbox breather, the crank seals are new and lovely.

    So, all those breathers coming off the carb (pwm38) and the gearbox breather go under the bike, make a mess, and can allow water in if the riding conditions permit... why not route them all to the redundant coolant overflow bottle at the rear of the bike (use top as inlet and loop bottom pipe over frame to stop it emptying and still allowing atmospheric pressure)...


    So... genius? ;)
  2. dirt bike dave

    dirt bike dave Sponsoring Member

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    Not a good idea to route the 'other' overflow tubes into the coolant recovery tank.

    First, why take a chance that you will suck crud into your coolant? Also, you will have a grativty feed from the coolant recovery tank to your carb and gearbox. Something is bound to get sucked back up.

    I think a better idea is to remove your coolant recovery tank completely and save a little weight. Leave your carb and gearbox breather hoses where they are, but trim them and cut the dangly ends at a 45 degree angle to they are less likely to get clogged up and/or suck stuff up.

    As for the drool on your shop floor, my solution is to put a rag under your bike, lol.
  3. motopsycho87

    motopsycho87 Rookie DRN Member

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    I proof read what I wrote and thought to myself "surely no-one will assume that I will leave the radiator connected to the coolant OVERFLOW tank"... apparently I was wrong :p.

    And even if I did, no matter what it cannot end up in the coolant. Pressure opens the valve to the bottle, negative pressure (when the system cools down) only seals the system tighter, there is no possible way anything can go from the bottle, to the radiator. You have to remember that this bike's cooling system is not like most cars or sports bikes that incorporate a EXPANSION reservoir, the KDX has a closed system with nothing buy a pressure relief.

    So basically, I am using the overflow bottle as an overflow for the gearbox and carb, and like I said, by connecting the top pipe to the gearbox and carb, then looping the bottom pipe over the frame and into thin air, unless the bottle somehow fills to the top, there is no possible way of contaminating fluids.
  4. sr5bidder

    sr5bidder Rookie DRN Member

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    Some of the vents on the carb are for overflow and I don't see any way they would be able to perform their function when the overflow tank is higher than the vent/ overflow tubes at the carb.

    I agree with dirt bike Dave and will add to the 45 degree cut a v shaped slit to make it like a snake tongue
  5. motopsycho87

    motopsycho87 Rookie DRN Member

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    Yes the centre breather from the carb is overflow, the rest are breathers.

    I've done it and THE BIKE STILL RUNS!!! OMFG hOW<!>!?!>?>?!>!
  6. pesky nz

    pesky nz Rookie DRN Member

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    The coolant can get back from the oveflow into the radiator by way of a one way valve (circular rubber flap in your radiator cap) as the radiator cools and the coolant shrinks. Once your catch tank gets enough fluid to cover the end of all your hoses the carb will stop breathing and you will experience a bad jetting change, usually about equall to pulling on the choke, so for my money I leave all but one carb breather down and one breather up as high as possible under the fuel tank. Then drill a small hole into my airbox near the top for the gearbox breather to firmly be pressed into( so water does not get into the gearbox untill the air filter is under water)
  7. mudpack

    mudpack Rookie DRN Member

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    Then something else is not right.
    ....and routing the lines to a "catch-can" will not cure the illness, only alleviate the symptoms. Find out what is wrong with the bike and fix it.
    My own KDX200 never leaks anything, and that's how they were designed.
    Fix it.
  8. motopsycho87

    motopsycho87 Rookie DRN Member

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    Does the 3 holes behind the flywheel and clutch that don't seal properly cause this problem?
    Last edited: Apr 4, 2012
  9. duncanstives

    duncanstives Member DRN Member

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    Mine doesn't leak anything either.... Not sure on the merits of the idea but don't think its supposed to leak unless its turned on its side or something in which case it leaks a little fuel from the carb bowl.
  10. motopsycho87

    motopsycho87 Rookie DRN Member

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    I figured out why it leaks now that I have my spare engine stripped. The pipe that leads out of the engine for the breather on my spare engine has a 90 degree bend in it pointing up, the current engine has a straight pipe coming out, meaning oil can escape via splash!

    God its easy to split the cranks on these!

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