Help a newb set up his first build!!

Discussion in 'Motorized Bicycle General Discussion' started by DV8, Jun 18, 2011.

  1. DV8

    DV8 New Member

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    First off hi all, glad to be here been lurking around for awhile trying to figure what would be best for me to run, but have a few questions/concerns that i haven't found enough info on yet

    Let me first list my bike and what i plan on running...
    08 Hardrock pro 19"
    49cc HS w G4 drive
    SBP shift kit

    Now to my questions i live up at 6000ft and wondering how the 4 stroke works in the slightly thinner air?
    How will it climb up the 13 mile at 8% grade then 3 mile 15% switchbacks, what kinda speeds would i be looking at, pedal assist is no prob

    I ride down everyday so am wondering if i need a diff clutch or something to disengage for going down or will the SBP freewheel take care of that? (again sorry for being so new to this)

    And now fit, i used the 9.5in x 8in template and i have about an in on the top left corner where the top tube drops will i be alright or would i need to relocate the carb or something to make it fit?

    Thanks all for the help!!
     
  2. rustycase

    rustycase Gutter Rider

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    Glad to hear pedal assist is no prob for you! LoL Yer little cina motor is gonna need help !

    8% grade at 6kft elevation is a serious task for any small engine.

    IIRC, small engines lose 10% horsepower per 1,000ft above sea level.
    ...and you are NOT starting out with much!

    Begin with 2hp. Take that to 6k ft above sea level, on a good day, you'll be smoking the dyno at 1hp!

    I see GEARS in your future. :)
    rc
     
  3. DV8

    DV8 New Member

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    Wow 10% loss per 1000ft is way worse then i was thinking,
    I'm beginning to think the last 3 miles of 15% grade switchbacks, which start at 5000ft is gonna blow that thing up!!

    Well i was imagining i would need to have a shift kit to help with the mountain but I'm 2nd guessing if i could still make it all the way up now....

    49cc+shift kit+15% mountain=BOOM?? :eek: lol
     
  4. Wippenshox

    Wippenshox New Member

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    That's very interesting. It also makes me feel better, knowing that I'm only 10ft above sea level.
     
  5. rustycase

    rustycase Gutter Rider

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    DV8... Yes, a shifter bike will be very valuable for you... with the ups and downs, then the BIG ups!

    At 6k ft, it will be a real trial for the little china girl... but it will do it!
    You are going to have to FEEL your motor... and operate it accordingly.

    ...Wshox... Yah, sea level is great! I learned about small engines at maybe 500ft above sea level at the most... then I found myself at 5k to 6k trying to make dirtbikes, chainsaws, and dredges get the task done... it was a whole different world!

    It's all good!
    rc
     
  6. Allen_Wrench

    Allen_Wrench Resident Mad Scientist

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    Would an electric be out of the question? I don't know enough about the brands to recommend one, but I do know it would not care if it were driving across the moon. Air or no air, it'd run about the same. And I seem to remember a video of a guy who built a downright dangerous electric bike. I won't underestimate 'em anymore. A good electric build can really kick butt.
     
  7. daRog

    daRog New Member

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    I can't vouch for its accuracy, but there's an altitude\HP calculator here:

    Wallace Racing - Braking HP Loss at Altitude Calculator
     
  8. DV8

    DV8 New Member

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    I haven't looked at elect kits enough but the extra lbs from the batt lack of range i need and not finding any kits that will be geared just didn't seem like the right option for me.
    Plus looking at the calc that was posted by darog seems that id be losing only 15% power not 60% so its gonna be slow but with the right gearing I'm sure ill be alright.
     
  9. DV8

    DV8 New Member

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    I sure do hope its accurate the 15% that it spit out sure is alot better then 60% loss. I'm just gonna have to run it for my self and see, thanks
     
  10. DV8

    DV8 New Member

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    I do appreciate all te help with the altitude questions i had.
    Now would someone be able to put my mind at easy as far as the fit? the 9.5 in template doesn't fit completely free and clear

    Pics worth a thousand words so i attached showing a 6" base and moved up to 8" if thats required (Ive read both)

    So I'm wondering if i can still get it to fit or if theres something i could do to jam it in so to speak, move the carb change the angle of the motor etc etc
     

    Attached Files:

  11. daRog

    daRog New Member

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    Have you considered doing a rear rackmount? You don't have a lot of in-frame space to spare.
     
  12. DV8

    DV8 New Member

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    i would really like to keep it in frame in fact id go out and pick up a bike with more room if i HAVE to instead of rear mount

    i was originally thinking of going with a Honda gx35 cuz of the limited space i have, but i doubt that make it up the mountain even with the gears.

    Anyways i still would like to no if i can make it work somehow, or anyone with exp or tips on working with limited space
     

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