2 stroke revival

Discussion in '2 smokers' started by Chillis, Dec 28, 2013.

  1. Chillis

    Chillis Long timer

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    Since there are no other dedicated 2 stroke sections I will post this here.

    http://www.cycleworld.com/2012/08/13/two-stroke-resurrection/

    What happened to this?

    Does anyone have thoughts on two stroke direct injection without using the case as part of the induction?

    My Aprilia for example, it uses the onboard air compressor to inject fuel and air into the combustion chamber. Part of the air volume comes from the case induction(95psi) and the compressor adds another 50psi +/-.

    The idea being no intake port, just forced induction of fuel and air and then an exhaust port. Crank has oil bath like 4 stroke.

    Thoughts?
    #1
  2. tHEtREV

    tHEtREV Captain Awesome... tEAM iDIOT.

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    It gets discussed every year or so.

    Last I had read KTM had it ready to go, but they put it to there distributors and they didn't feel that the buying public were willing to pay the extra for DI at this time.

    So I guess we will be waiting until there hand is forced.
    #2
  3. Kiba

    Kiba Dances With Huskies

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    I seems like some manufacturer or a startup no one has ever heard of talks about this every six months. I'd love to see it in action.

    I'm not even thinking about its application in dirtbikes. I'm thinking of a modern version of an RD400 or CR500 dualsport I could ride on the street without the EPA complaining. :D
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  4. Sp4rks

    Sp4rks Been here awhile

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    KTM really does push their 2 strokes more than any other major brand. They have the incentive(who would't want a DFI 2 stroke), resources(already shit ton of their own highly developed 2 strokes), and now the technology(if they didn't have it before, they do now with the acquisition of Husquvarna). And personally, I like the sound of "KTM, resurrector of the 2 stroke engine".:deal
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  5. Chillis

    Chillis Long timer

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  6. przjohn

    przjohn Been here awhile

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    I'm a big 2 stroke fan but to imply that the injection technology is big in outboards is quite a stretch. Walk around any marina and it is a floating billboard for Yamaha 4 strokes.
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  7. Chillis

    Chillis Long timer

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  8. WIsixfitty

    WIsixfitty ceiling unlimited

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    Ski-Doo/BRP 2s sleds, while still maintaining the 2 stroke qualities get better gas mileage than any 4s sled.

    Polaris and Artco also have direct enjected 2 strokes.
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  9. ericm

    ericm Long timer

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    I'd love to see someone use Honda's Activated Radical technology. I had a chance to ride their EXP-2 402cc Baja bike and it was very smooth, powerful and ran clean. The AR tech increased mileage (a big concern for Baja/Dakar).

    However as the article points out emissions regs for watercraft are not nearly as strict as for road going vehicles. DI case charged two-strokes still need some oil in the intake air for piston lubrication. Even with direct injection to bearings some of that oil will end up being combusted as well.

    Using a supercharger to provide intake air does address those issues, and would allow for lighter and more durable plain bearings in the crank. But it does add about as much weight and complexity as a four stroke cylinder head with poppet valves. So you're not saving much.

    But the key to why we won't see it is also in the article- boaters and snomobilers rebelled at the added cost and weight of four strokes. While motorcyclists have pretty much accepted them, helped by racing regulations which discouraged or banned two-strokes. The big motorcycle makers felt that four strokes were the future so they made it a self-fulfilling prophecy.
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  10. regomodo

    regomodo Been here awhile

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    FWIW, I was at a Kawasaki enduro day this month and Mick Extance, who is a Dakar rider sponsored by Kawasaki, mentioned Kawasaki are looking to bring back a 2-stroke line.

    Sent from my Nexus 7 using Tapatalk
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  11. tHEtREV

    tHEtREV Captain Awesome... tEAM iDIOT.

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    Hmmm, Modern KDX200.:tb
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  12. anonny

    anonny What could go wrong?

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    I ride a Ski-doo 600 Eteck (direct injected 2 stroke) as my work sled and it absolutely rocks.... 120 hp out of 600 cc box stock. Starts first pull even after being in storage for 6 months, gets awesome fuel mileage, hardly burns any oil and doesn't smoke....... even on start up.

    Cant wait till someone comes out with a DI dirtbike around 300 cc's.
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  13. dhallilama

    dhallilama Long timer

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    if (when?) a manufacturer makes a DI 2 stroke dirtbike... particularly if it's street legal... it might just renew my interest in new motorcycles.

    something in the 300cc range that doesn't suck fuel down like a Hummer & has a fair environmental impact... ok, i ride old bikes... i mainly say that 'cause the chicks like it... i'm mostly in for the mileage. a modern, light weight, DI 2T... i could go for that.
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  14. WIsixfitty

    WIsixfitty ceiling unlimited

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    The 300exc has a stroke of 72mm.

    600 ETEC has a stroke of 73mm.


    Hmmmm?:1drink
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  15. Bump Stop

    Bump Stop 2 Wheeled Drifter

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    Is anyone producing a single that is DI? I'm wondering if multi cylinder engines are easier to make work properly.
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  16. WIsixfitty

    WIsixfitty ceiling unlimited

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    Ski-Doo's etec twin can easily be converted to a single, or mounted on a single. They're basically singles joined together.


    Unfortunately I don't forsee any OEM doing this as it would'nt be a good money making business decision.
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  17. tHEtREV

    tHEtREV Captain Awesome... tEAM iDIOT.

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    Isn't there a handful of 50cc scooters that are DI?

    Edit, yep, the OP even says he has one in the first post.
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  18. Bump Stop

    Bump Stop 2 Wheeled Drifter

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    I didn't read the whole OP, so the DI single is sounds too complicated for the typical dirtbike.
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  19. tHEtREV

    tHEtREV Captain Awesome... tEAM iDIOT.

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    Yeah, I thought that too a while ago.

    I was wondering where the DI bikes are if the technology was already out there, and thought there must be a big down side because it isn't.

    But after reading an article in a mag that said KTM have a working DI bike, but it is going to add a significant amount to the price and the distributors don't believe that buying public will pay the extra, I could see where the down side is.

    DI sounds good, but I'm still suspicious.:deal

    (But having said that, I'm in a country that you can still by a 2 stroke of the dealers floor in street legal trim...)
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  20. tHEtREV

    tHEtREV Captain Awesome... tEAM iDIOT.

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    I went searching and found the article, and it would appear I was a bit wrong...

    It is a small part of Dirt Action magazine July 13 issue 170 on the 14 MY KTM range, and it says...


    So they are saying EFI, but it could be a stuff up on the writers part, because I can't really see EFI adding any significant weight...

    And I have seen mags claim that the Ossa is DI and not EFI, so they may still be talking about DI and not EFI...
    #20