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  1. #21
    jetskibruce's Avatar
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    Quote Originally Posted by Rip'nTear SHO View Post
    This is the poor man's way of blocking off hot PCV air from re-entering the air intake on your SHO. Thanks to Cuchun as I saw this done on his GPR-SHO conversion. All you need is 3/4 heater hose block off and a $7-8 stainless breather from Pep Boys................
    Just curious - how much hot air do you think is blowing by the piston rings and needing to go back into the engine? I don't think it matters much either way - it's not like an egr. However, if a piston develops a hole (heaven forbid it) you might want the gases to go back into the engine and out the exhaust.

  2. #22
    you can feel air blowing through the pipe at idle i dont know about full throttle....
    the tech at my dealer said that if you overfill the oil it will overflow through that pipe...

  3. #23
    jetskibruce's Avatar
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    The HOs are sensitive to too much oil. I wipe a film of oil out of the HO breather box over the PCV hose after each ride. There has to be some blow-by to do that, I don't think it can all be expansion.

  4. #24
    Hydrotoys's Avatar
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    Stock, and New, you won't see a need. Once you actually UP the boost, then the SHO/FZR will be subject to the same blowby as any other engine under hi-boost. There is no free lunch.

  5. #25
    jetskibruce's Avatar
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    Right, there will be a little more blow-by (and more with age). So now the hot oily air comes out past the newly added breather and into the hull, where all the air is being sucked into the intake and it goes to the same place by a longer route?


  6. #26

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    Quote Originally Posted by jetskibruce View Post
    Right, there will be a little more blow-by (and more with age). So now the hot oily air comes out past the newly added breather and into the hull, where all the air is being sucked into the intake and it goes to the same place by a longer route?

    Unless you vent outside the back of the hull into the water. Yikes LOL

  7. #27
    jetskibruce's Avatar
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    Dragster headers can scavenge the crankcase into the exhaust at high rpm, but this is not class A inboard appropriate.

  8. #28
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    Quote Originally Posted by SHOBiz View Post
    Unless you vent outside the back of the hull into the water. Yikes LOL
    my seat has 3 holes on the back that vents so im good lol

  9. #29
    jetskibruce's Avatar
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    As I was looking into the racing engine info on some other web sites it seems that engines like a lower pressure in the crank case. The blow-by and pressure is highest at high rpm and power levels. Solutions are: a separate pump that has the capacity required, the exhaust scavenging, and the intake manifold. Seems like the tradeoff is some amount of hot air in the intake vs better performance with lower crankcase pressure. One potential problem with pressure in the crankcase was the real possibility of forced oil leaks. Seems like the yamaha engineers know what they are doing. lol

  10. #30

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    Huh?

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