Beginner bike.

Discussion in 'Bicycle Repair' started by Brendan, Feb 19, 2016.

  1. Brendan

    Brendan New Member

    I am building a motorized bike for my senior project in high school. I have a bike that works and I can mount the engine on. I was wondering if you guys had any suggestions or help you could give. Anything can help, engine suggestions, mounting suggestions, especially dealer suggestions. Thanks!

  2. bakaneko

    bakaneko Active Member

    From an academic and tinkering perspective, there are pro and cons of a 2-stroke and 4-stroke. I listed some below. Overall, for an academic project I would go with a 2-stroke engine kit.

    - more customization and engineering decisions for component parts
    - engine is open so you can take it apart and tinker
    - cheaper than 4-stroke
    - more difficult to assemble and mount but there is engineering lessons behind that
    - requires using a clutch to operate but working the clutch helps in case you want to ride a motorcycle in the future

    - engine is more complicated but the engine kits are really not meant to be disassembled
    - more expensive than 2-stroke
    - no clutch so both hands free for braking and easier to use
    - while the engine is complicated and has more engineering, because it is "premade" it really doesn't engage you in the science and engineering behind engines like a 2-stroke

    From a practicality and reliability perspective, a 4-stroke is better.
  3. JunkyardDog

    JunkyardDog Active Member

    I agree with the 2 stroke. The one HUGE drawback to any kit that uses one is the cheap clamp on chain tensioner/idler. It would be great if you could come up with an alternative. The rag joint rear sprocket is also a weak point, but the aftermarket already came up with a couple of solutions to that. I'm surprised that nobody has bothered to come up with a good solution for that tensioner.
  4. bakaneko

    bakaneko Active Member

  5. HeadSmess

    HeadSmess Well-Known Member

    if its a "senior high-school project" and you are buying parts then simply bolting it on...i would give you an F-.

    show some skill in using the lathe, a welder, some design and fabrication, and check out some engineering basics... possibly an A, even if it doesnt work properly. its a first attempt...

    ie, no kits.

    you can have a clutch on a run a slip belt clutch, remove the starter and the centrifugal clutch, and with some luck you can just squeeze it between the cranks. (i might even give you an A+ if you made a decent clutch mechanism, or did something else unusual...)

    you can rack mount, use either friction drive (useless in the wet but this is only a project, not a necessity, so thats irrelevant) or chain drive. end of high school...i was using friction drive with an over-center locking clutch thingy.

    either way, you can show that you can fabricate something from scratch... but then, the education system passes anyone and everyone these days, so...just buy a kit and be lazy :) leaves more time to go out and party, huh?
    KenM likes this.
  6. bakaneko

    bakaneko Active Member

    Well. It really depends on the class the project is for. If it is a machine shop class or something then yes simply assembling the kit is not adequate for a project. But for either a physics or general science class, I think putting the kit together and then really researching the science and engineering behind the engine/kit is a good project. There is a lot in the engineering and science behind these kits and really flushing it out in a project format is a good project, imo.
  7. JunkyardDog

    JunkyardDog Active Member

    Is there such a kit that can be simply bolted on without a lot of fabrication, especially when it comes to those Chinese HT kits?
  8. Brendan

    Brendan New Member

    Is that tensioner what you connect to the throttle to engage the the engine, I was thinking about making something myself to do it.
  9. Brendan

    Brendan New Member

    No, I'm not going to get a kit, I'm just going to buy the engine and maybe the throttle myself.
  10. Brendan

    Brendan New Member

    It has to be engineering related but we present to our english teacher so I could say that the clutch is a ukravtoprom and she'd probably buy it.
  11. bakaneko

    bakaneko Active Member

    Umm, listen, everyone would love as a learning experience for you to do as much as possibly can by yourself without the kit. But, if this is for an English class, I presume a presentation/communication project, than there is no need to go and 100% McGuyer the 2-stroke engine. The kits are pretty good sans a few items and are designed for the force and complexity of the engine. I fear that if you try to install the engine without the kit then you will end up disappointed and frustrated with the results. The presentation material from installing the kit, understanding the engine, and explaining the history, usage, and legality of the kit is more than required for a good English presentation project. Just my 2 cents.