Why are there no PWC/ Jet Skis with V-Twin Harley-Style Engines?

Discussion in 'Jet Drives' started by Chris Hall, Aug 10, 2009.

  1. Chris Ostlind

    Chris Ostlind Previous Member

    Yes, I am, but I sense that you are referring to a specific application of the term, no?
  2. apex1

    apex1 Guest

  3. Chris Ostlind

    Chris Ostlind Previous Member

  4. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,945
    Likes: 167, Points: 63, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    Prob with HD v-twin in PWC is it is air-cooled, and tall.

    HD motors have enough problems with rear cylinder cooling when fully exposed.

    Plus, I think all PWC are required to have water-cooled exhaust as a fire safety.

    The only car fire I ever had was from a leaking value cover constantly leaking on the exhaust header. Appairently, it had to first build up some charbroiled oil to further reduce cooling for it to ignite.

    I do agree there would be an American market for Big Twin sounding PWC, but I'm not sure if it would be there for a Japanese liquid cooled Big Twin powered one "just because".

    PS-one of my back burner projects is to rig a simple electric fan on a air-cooled bike, because it would give me peace of mind when sitting in trafffic or chugging up a long slow steep road.

    Motor cycle salesmen will tell you it is not needed because the bikes have been pretty well thought out over the years, etc. Then they will tell you that your air-cooled bike should have the oil changed about twice as often as a water-cooled bike.

    Why? Because once the oil passes over a 'hot spot' the oil is basically 'burned' and not good.

    "So, if the oil passes over one of these hot spots just after a change then I'm riding around on BAD OIL until my next change?" they don't have an answer for that.

    Air cooled engines last about 1/2 as long.

    The Vespa Ciao moped has forced fan cooling with a shroud. I hear that "solves most problems".
  5. apex1

    apex1 Guest

  6. Chris Ostlind

    Chris Ostlind Previous Member

    What you are suggesting is just the opposite of what is done everytime a GP racer enters a turn. The bike is partially leaned and partially steered into the turn while breaking hard (sometimes through the apex depending on entry speed) and then it is gassed, up and out of the turn radius, setting up for the next turn, or straightaway.

    Equally so, and depending totally on the banking, the turn radius and the speed held through the entry, the bike might be braked only as it enters, while the power is applied smoothly and forcefully through the apex, as the machine exits the turn. Sometimes, the rear wheel loses traction incrementally and a rear wheel drift is the result for the talented riders... If one is really good, then both wheels can be drifted while turning... another way to successfully turn a motorcycle at speed that also violates all the rules one typically learns.

    We can go on and on like this for days, but it won't change the reality of what happens when a motorcycle is braking while going through a turn. If I am not making this clear with my descriptions, I apologize.
  7. apex1

    apex1 Guest

    Still have NO clue what your question was, sorry. And after all the first timers lessons, we had to know what I described above, braking when going through a turn brings the bike upright, thats it! And its a nono.
    That has nothing to do with braking, and is not as difficult as it might look.
    A good driver can do a lot of things the average amateur should better leave, but from 1967 `til now I have not seen one of them braking in a turn, without loosing precious parts of the bike or the dining room furnishing.
  8. Frosty

    Frosty Previous Member

    There are 2 kinds of bikers. there is the biker that watches the Grand prix then gets his leathers on and goes for a ride, (I wonder what he is thinking) taking corners on oublic roads as if he was---well you know.
    A menace to the public and probably would not be aware of an accident he was responsable for a mile bacK down the road.
    The kind of biker that even bikers dont want to see, the kind of biker that most European countries are trying to regulate out of existence.

    Then there is the cruiser, the Vtwin. This guy drives down the road , back straight enjoying the weather and the flora and fauna, the rumble of his bike is enjoyable, stopping at lights to say hello to the old lady
    and helping another early morning rider on his way.

    Tiping his helmet to the vicar as he rides through the town, every one smiles and cheers.

    Organised cruises are available in most countries and bikes such as Royal Enfields are used.
    Gp wanna be's are a menace to the public road.
  9. Ike
    Joined: Apr 2006
    Posts: 2,651
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    Location: Washington

    Ike Senior Member

    Actually the first PWC engines were based on motorcycle engines, escpecially the Kawasaki Jet Ski and the Yamaha pwcs. But they had to make significant changes to them because they are in a boat. Motorcylce engines are out in the open air, PWC engines are enclosed. So you get into breathing issues and ventilation issues. Plus they don't have a transmission in the motocycle sense so this meant changes to cams and timing and various other things. But one of the big factors was keeping water out. How do you keep the engine running when the pwc is upside down and water is puring in the intakes? PWC engines are designed to keep on running upside down or if the pwc is "catching air".

    On top of that they had to satisfy USCG safety issues with fuel and electrical systems, how to draw from a fuel tank upside down, and so on. The current engiens in pwcs are pretty amazing, and they have gotten much quieter, and the Yamahas even have catalytic converters. You won't find that on a Harley. now days they have to meet all the USCG safety regs, the EPA, and California environmental regulations as well.

    So, yeah, you could drop a harley engine into a PWC but you would have some serious issues to solve, one of the biggest would be the added weight. But it would be a real mess to sort out the problems.
  10. apex1

    apex1 Guest

    There is a third group Frosty! They sit already on their bikes when the GP races happen, because it is weekend then, and they like to bike not to watch biking! And the wannabe´s are not long enough with us to be a real menace, their own nature sorts them out quickly.
  11. Frosty

    Frosty Previous Member

    Strange !!! Im sure I left a hat for you there,--its on the 1st peg.
  12. jtd
    Joined: Feb 2008
    Posts: 8
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: mn.

    jtd Junior Member

    after reading this question and all the posts I cant help but reply with a simple answer " because it's not practical"

    if you just want the sound and don't care how or if it will perform, then you should try to get that hd v twin in a pwc .

    but this is like asking why cant you buy a corvett with a 4-cyl.
  13. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    What's practical about a PWC?
  14. Submarine Tom

    Submarine Tom Previous Member

    Do It!

    Blah, blah, blah, just do it. Why not? If you're talking about it, do it!

    I rode and raced an RZ350 for seven years and thank you for the trip down memory lane but come on,

    why not put a 400 hp turbine in a PWC?

    They're small, light and have awesome transmissions available.

    "Talk's cheap 'till you get the bill."

    So, Chris Hall, when's your projected completion date?

    Any drawings to show?

    Yipee kiay,


  15. Frosty

    Frosty Previous Member

    You name submarine tom is a dead giveaway to your fearless approach to making crazy stuff .However a 400HP turbine in a jet ski is pushing out the boat a bit.
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