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Help Zeal smoking from gearbox

Discussion in 'Yamaha 250cc In-Line 4's' started by Pyr0technicien, Jun 15, 2019.

  1. Pyr0technicien

    Pyr0technicien Member

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    Hey people,

    My gearbox has been smoking for a while, I realised that in the rain last week and tought it was just water evaporating.

    However It's not raining today and the smoke (exhaust gas) is coming out of the hose plugged into the top of the gearbox.

    I'm not sure what this hose is for, but i guess it's to drain oil split or something. I've seen the same on my DR350.

    Could anyone tell me what's the purpose of the hose (it's plugged at the top of the gearbox on one side and not plugged to anything at the other end). The hose is really oily. if i shake it some oil will fall from it.

    But I guess the smoke isn't something normal, however the bike is running properly, and I don't know since when it's smoking like that.

    Thanks for the help !
     
  2. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    The hose is a gearbox/bottom end breather tube.
    It's definately smoke not steam ?

    If it is oil blue/grey oil smoke you might be getting a bit of blowby past the ring's
    Using some Threebond Super Engine Conditioner (petrol version, $15 from behind the counter at Repco) in your top end may help to clean the ring's enough to get it sealing again nicely
     
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    Last edited: Jun 15, 2019
  3. Pyr0technicien

    Pyr0technicien Member

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    I'm always by how fast replies are in here :)

    Well I would say it's not steam since it smoke all the time, and there is no water around. I would have steam only when I start the engine I guess.

    The funny thing is that it smoke from there but not from the exhaust. The bike used to smoke on high rev trough the exhaust pipes, hard to see while riding but at idle it doesn't smoke, only from the breather.

    What do you mean by top end ? trough the windows used to do the valve clearance ? or in the oil tank ?

    The smoke is more or less white (not sure if that's considered like blue), but the bike doesn't really consume any oil, i never have to top it up.
     
  4. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Put some tissue's over the end of the breather tube and catch some of the smoke/steam for about 10 - 20 second's,
    then take the tissue away and let it dry, if it's oily you'll see it wet still after a while, if it's steam it should evaporate.
    Has the bike been sitting unused for a while ?

    The Threebond get's sprayed into each cylinder through a vacuum tube on each individual intake manifold or you can also spray it in through a spark plug thread (refit spark plug after spraying it in),
    it's help break down any oil oil / carbon etc on your piston crown and inside the combustion chamber.
    It also get's down between the piston and ring's and if there's any sludge built up there it'll loosen it so when you start the bike it'll burn it out and the ring's might be able to seal properly again


    Threebond Engine Conditioner (Petrol) cleans the induction system & combustion chamber on your petrol engine by removing carbon, varnish, sludge & gum all without dismantling major parts of the engine.
    IMPROVES PERFORMANCE REDUCES PINGING IMPROVES FUEL ECONOMY HELPS SMOOTH ROUGH IDLE REDUCES POLLUTION HELPS COMPRESSION RATIO
    Use every 15 000km service or 6 monthly.
    Suitable for vehicles with catalytic converters O2 sensor safe
    Use only on cable-operated throttle, if electronic throttle consult your dealer BEFORE using. NOT TO BE USED ON DIESEL ENGINES - SEE Threebond Engine Condition Diesel 3B-DEC No CFC LPG Propellant Flammable Gas 2

    INSTRUCTIONS FOR USE: Warm engine to normal operating temperature. Shake can well. Stop engine, remove a convenient vacuum hose from intake manifold/throttle body. Spray for approx. 15 seconds. Allow to stand for 5 minutes before proceeding to next step. Start engine and accelerate enough so that the engine doesn't stall. Empty remainder of can into intake manifold/throttle body. When can is nearly empty stop engine and allow remainder of conditioner to sit for a further 5 minutes. Re-attach vacuum hose. Start vehicle and run for minimum 2 minutes before road testing vehicle.

    When

    you get it started and running it'll need a bit of throttle for a little while, it will smoke out the exhaust for a while, may be a lot of smoke too, but it will eventually burn off any oil/carbon build up on the piston's and rings's etc and run nice again
    Then once the smoke stop's take it out for a decent ride and check if the breather is still smoking or not
     
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    Last edited: Jun 15, 2019
  5. Pyr0technicien

    Pyr0technicien Member

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    Well I think the bike would definitly need a bit of cleaning that's true. I always tought those product were a bit of black magic but I'll give it a try.

    Is there any vacuum intake on the zeal ? If not I'll have to repeat that step for every cylinder trough de spark plugs.
    I'll try that Tissue technique straight away !
     
  6. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    Subaru Dealer's / Workshop's recommend's cleaning out the combustion chamber's, ring's and piston's etc regularly doing it that way.
    They use the same product too from what i have heard.
     
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  7. Pyr0technicien

    Pyr0technicien Member

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    Hey for closing this post.
    My bike really struggled at some point. I realised it was all good without muffler.

    So I took the muffler appart and it was full of deposit. Also muffler is starting to close itself due to the heat ( it's not the original muffler of the fzx250 tough, handmade one). So that doesn't help either.

    But since the muffler has been clean, it doesn't smoke from the gearbox anymore.
     
  8. ruckusman

    ruckusman White Mans Magic Master Premium Member Dirty Wheel Club

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    Sounds like it may have been excessive backpressure from the clogged muffler pushing exhaust gases past the rings

    Given that exhaust gases contain all sorts of nasties, I would definitely change the oil now that it is running properly again
     
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