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Bikes with two engines?

Discussion in 'Motorcycle Related Discussions' started by speirmoor, Feb 6, 2018.

  1. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    The purpose of adding cylinders in this instance is to add the CCs that are within!

    It’s a 1500cc 2 stroke made from two genuine racing engines (not just some old road bike junk...).

    I think it’s a work of art!
     
  2. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    What would the power to weight ratio be like ? With a drag bike, inertia is still a problem. If you build something like that, you have to live with it. Changing jets in a twin cylinder two-stroke is almost too much work for me. Imagine stuffing around with the ignition system and carburation on that after you have encountered detonation ?
     
  3. Danno

    Danno

    Joined:
    Feb 7, 2010
    If you've ever watched a Top Fuel team rebuild an engine between heat races, you wouldn't think rejettting eight carburetors was such a big deal. Amazed onlookers are randomly handed parts that won't make the next race as souvenirs.
     
  4. trident sam

    trident sam

    Joined:
    Oct 23, 2012
    Not sure if this is fairly common but there's a guy round where I live with a road legal TZ 750, it certainly doesn't lack power !!!
    sam
     
  5. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    I think a double TZ750 is silly stuff. A normal TZ750 is quick enough for anyone, regardless of what kind of racing they are doing. A couple of my friends were playing with one. They reckon that when you blast it down a straight, the end of the straight tends to get much narrower. The guys I knew who used to race them in A Grade were all exceptional riders, - not for beginners.
     
  6. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    Only to an inert mechanic :oops:
     
  7. Danno

    Danno

    Joined:
    Feb 7, 2010
    In the day, a twin-enginned Norton was silly stuff, but Hogslayer rests in England's National Motorcycle Museum. I'm sure when TC and John started out, they just wanted to have a good time and win some dragraces. Having camped next to them at a rally years ago, I can attest they never forgot about the fun and only got serious when the bike was staged.
     
  8. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    Having fun is what motorcycle competition is all about. But you need to see a return on investment. It is no fun getting thrashed.
    I would ride a double-engine Norton, but I would not touch a double TZ750 with a barge pole. A normal TZ750 is too much for most guys. You don't need to make a mistake. The frame I have in my shed was copied from the Egli TZ750 which Graeme Muir rode to a win in the Swann Series at Sandown in about 1979. He won because the Egli frame was much better than that of the D model TZ750, and prior to that the Japanese frames were even worse. How would you be trying to make a frame for that 1500cc version ?
     
    Last edited: Mar 12, 2018
  9. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    An Egli TZ 750? Now that sounds like an interesting idea !
     
  10. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    It was a mid 70's two-stroke frame which Fritz Egli produced specifically for the TZ750. Muir rode it around every other rider in that round of the Swann Series. The bike is still in Dandenong near Melbourne. It would cost an arm and a leg to race it again. And there is really no class for it these days. Who owns it these days is a matter of dispute.

     
  11. acotrel

    acotrel

    Joined:
    Jun 30, 2012
  12. Mark

    Mark

    Joined:
    Aug 8, 2006
    ^ it's gonna take a bit of work to get two engines to fit in that frame.
     
  13. acotrel

    acotrel

    Joined:
    Jun 30, 2012
    That doubled TZ750 would be hopeless. I cannot think of a way, you would ever make a safe bike using it. Having a theory is one thing, but doing it is usually quite another. It is like that old 'you put the best motor in the best frame and you should have the best bike' - it does not usually work that way !
     
  14. Danno

    Danno

    Joined:
    Feb 7, 2010
    I was asked to organize a display of old magazines an photos for a pre-race party at the Garage Mahal. Couldn't figure how to rotate this image upright, but if the powers that be can, feel free.

    [​IMG]
     
  15. Fast Eddie

    Fast Eddie VIP MEMBER

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    Oct 4, 2013
    What’s the correct formula then Al?

    Worst engine in the worst chassis ??
     
  16. cehenard

    cehenard VIP MEMBER

    Joined:
    Sep 29, 2014
    Sometimes excess is best I guess.



    I've always admired the "Engineuity" but I'm pretty contented with motorcycles that I can ride and have fun with, and a chainsaw that starts, runs, and cuts wood that won't wear my old tired ass out while it's doing it. Plastic surgeons kinda do similar things nowadays, but there's a point where excess is just a mess. To build something for a purpose is great but to do it just because you can is usually a waste.

    Charlie
     
  17. Danno

    Danno

    Joined:
    Feb 7, 2010
    Another from the old mags.

    [​IMG]
     
  18. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
  19. acotrel

    acotrel

    Joined:
    Jun 30, 2012

    Eddie, you would think a 60 BHP 750 commando engine in a featherbed frame would be the best bike, however a good guy on a 50 BHP 500cc Manx would probably beat the pants off it. The chassis must be designed to suit the motor. I've ridden 650cc Tritons and one Manx - the latter was far superior. A Triton is only faster in a straight line - impossible to corner one as fast as a Manx The motor is usually too far back.
     
    Last edited: Mar 22, 2018
  20. Danno

    Danno

    Joined:
    Feb 7, 2010
    thanks for spinning that one, Ken. ! couldn't do it on my photo-hosting site.
     
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