Best starting place

Discussion in 'Motorized Bicycle General Discussion' started by Swiftyhernandez, Jul 11, 2014.

  1. Swiftyhernandez

    Swiftyhernandez New Member

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    Hello all!
    I am new to motor-bicycling, but I have many years of 2-stroke experience.
    I plan on building from parts, my bike, and will not start with the "complete kit."
    For the engine, I intend to port the cylinder and cut the piston; and certain add high-performance intake/exhaust/ignition pieces; an effort to make more power than stock.
    For a starting place, please help me to understand which bottom-end is best?
    Extra points for explaining "why" :)

    Thanks!!!
    Swifty
     
  2. BobbyT

    BobbyT Member

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    Do you have experience with china 2stroke's? If you start with what you think are modifacation's how will you know what you have gained with your mod's. A kit may help you save money with your build.
     
  3. greaser_monkey_87

    greaser_monkey_87 New Member

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    Agreed. There is no high performance ignition for the china 2 strokes, some claim to be but in speed tests they prove the same or worse than stock. Porting the cylinder, cutting the piston and using a performance head and exhaust are what's going to get you the most power with these engines. I also recommend a bigger carb than stock. Reed valves also help. But I would recommend starting with a stock engine and breaking it in before starting any mods.
     
  4. Swiftyhernandez

    Swiftyhernandez New Member

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    I ported the top-end on one of my brother's bikes and helped to install motors in a couple of others; I am familiar with he standard kit, knowing it contains many parts I have no intention of using.
    My desire now it to build my own bike, port it and install a better, tun-able carburetor; among other modifications. This is why I want to start with the best crank/bottom-end that I can afford.
    [​IMG]
    [​IMG]
     
    #4 Swiftyhernandez, Jul 12, 2014
    Last edited: Jul 13, 2014
  5. maniac57

    maniac57 Old, Fat, and still faster than you

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    Buy a 40mm stroke bottom end from MotorBicycleRacing or Dax for the best bottom end.
    Neil's (MotorBicycleRacing) cost a bit less. PM him for details.
    I love my "GenV" engine which is based on the longer stroke crank.
    They have a better "balanced" crank from the factory.
     
  6. greaser_monkey_87

    greaser_monkey_87 New Member

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    Any carb is tunable, drill the jet.
     
  7. Davezilla

    Davezilla New Member

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    I agree.. in most cases the standard NT carb will do just fine after jetting it proper by either drilling it up or soldering it shut and then drilling it smaller etc... I've used several different types of carbs on mine and the standard NT is the easiest to get right and will make decent power for most setups. The speed carb isn't bad but it's not as reliable as the NT.
     
  8. Swiftyhernandez

    Swiftyhernandez New Member

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    [​IMG]

    [​IMG]

    [​IMG]


    Here it is...my First Motorized bicycle build!
    Tomorrow morning, I shall start and ride it for the first time.
    Wish me luck drn2
     
  9. KCvale

    KCvale Active Member

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    That looks like a decent bike, dual V-brakes, but your carb won't function sideways like this.

    [​IMG]

    I know, it's not attached, just funing with ya ;-}

    I would however suggest you loose all that rubber in your motor mounts and bolt down hard to frame.

    The simple rule of thumb test for a proper engine mount is to grab the top bar with one hand and the top of the head with the other hand and shove back and forth as hard as you can, if it moves AT ALL that is a fail.
     
    #9 KCvale, Jul 25, 2014
    Last edited: Jul 25, 2014
  10. 2door

    2door Moderator
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    Ditto on the rubber. It doesn't work and will cause you problems.

    You need to do a little research here and read about rubber mounting the engine and fenders. Fenders look great and serve a purpose but they can hurt you if they come loose or the braces fail. There are pages on both subjects. Use the search feature and key word/s.

    Tom
     
  11. Speedfreak241

    Speedfreak241 New Member

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    I second 2door on the fenders mine only lasted a couple days of riding before they cracked and broke off. Plus the chain will sometimes slap them and bind up.
     
  12. Citi-sporter

    Citi-sporter Member

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    The best starting place is to have the bike itself in as high a quality state of readiness, and double checked for tightness and adjustment as possible. This can't be over emphasized, bicycles are not normally meant to have engines added to them, Especially with engines can push the bike up to 30 mph on the flat.

    I think using rubber under the chain idler wheel mount is asking for trouble also. Some end up making this a permanent mount by welding it in place. The less you can have come loose on the bike, the better, because these engines buzz.
     
    #12 Citi-sporter, Jul 25, 2014
    Last edited: Jul 25, 2014
  13. Davezilla

    Davezilla New Member

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    I also agree on ditching the rubber on your mounts, mount it all nice and solid and it'll vibrate less and not tear up your frame or mounts. Use blue locktite on all your studs, and use lots of self locking nuts to help prevent things from working loose or backing out.
    Overall this is an excellent build and it looks Great
     
  14. joey1320

    joey1320 Member

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    Kind of hard to tell from this pic but it seems like your chain is really close to that fender, be careful it doesn't catch.

    Great looking ride dance1
     
  15. Davezilla

    Davezilla New Member

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    Easy solution for the fender to chain clearance issue (if there is an issue there) would be to cut out a few clearance notches in the fender similar to the clearance notch at the bottom/front of the rear fender where it need to clear the aft frame. This may require removing the rear fender to dremel out the notches and reinstalling it, but it's these little extra efforts that will make your installation and your bike last a really long time. Still a Very nice looking build, just take care of those subtle small details like this and the mounting and you'll have a very dependable ride.
     
  16. Swiftyhernandez

    Swiftyhernandez New Member

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    [​IMG]

    [​IMG]

    Thanks for the advise, guys, tho, I'd like to add: so far, so good!
     
  17. Swiftyhernandez

    Swiftyhernandez New Member

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    [​IMG]

    Losing the unnecessary chain-tensioning, idler wheel.
     
  18. Swiftyhernandez

    Swiftyhernandez New Member

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    Lessons learned or re-learned:

    Never over-estimate the performance of your tire.
    Never under-estimate how bad a small motorcycle can hurt you.

    Tires from Schwinn are for decoration purposes only.
     
  19. Swiftyhernandez

    Swiftyhernandez New Member

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    Don't bring a knife to a gun fight.
     
  20. Davezilla

    Davezilla New Member

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    ... and Never, Ever, play leapfrog with a unicorn... :eek:
     

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