79cc harbor freight? Or 212cc

Discussion in '4-Stroke Engines' started by Milkshake, Aug 4, 2016.

  1. Milkshake

    Milkshake New Member

    Hi guys, I'm new to motorized bicycles. I just bought a 49cc 4 stroke engine kit that is 2.5 horsepower. I weigh 203 pounds the engine is great going on flats but struggles on slight hills. So I'm going to upgrade. There are 2 harbor freight engines. 79cc 3 horsepower and 212cc 6.5 horsepower. Will the 79cc engine pull me up hills? My thoughts are what can a extra half horsepower do? Going from 2.5 horsepower to 3 horsepower doesn't seem like much of an upgrade. Help..... also I put a picture of my bike. Will the 212cc or 79cc engines even fit on my bike?
     

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  2. bakaneko

    bakaneko Active Member

    hi. i really don't understand where they are getting the 2.5 hp from. they advertised the max power in metric as 1.5KW which is ~2hp. since this is an Asian motor and from my experience, I feel 1.5KW or ~2HP is more sensible.

    Max Power(kw/r/min)
    1.5 KW / 2.5 HP / 6800


    also, the 3 hp for the 79cc predator is the governed hp. many people remove the governer to get beyond the 3600 max rpm. another good thing about the predator is that the clutch shoe comes with different springs so you can tailor the rpm you want to engage the transmission at.

    the bad thing is that you need to make or buy a throttle hook up.

    if you were to go the harbor freight route, i think you should keep your old bike and build on a new bike. ive seen the 79cc on regular bikes but you need to remove the tank, muffler, and possible the carb and replace them with racing/go-cart ones.
     
  3. Frankfort MB's

    Frankfort MB's Well-Known Member

    The 212 needs a huge frame btw:):p
     
  4. Milkshake

    Milkshake New Member

    What about my weight? Keep in mind I would like to go uphill at a decent speed. Will 3 hp be enough to pull 203 pounds plus the bike and engine? Or should I get the 6.5 hp.
     
  5. Milkshake

    Milkshake New Member

    Any recommendations on the frame?
     
  6. Frankfort MB's

    Frankfort MB's Well-Known Member

    I'm sure it will.... I think these motors make more power than they say

    The HT 2 stroke makes 1/2 what the company's say though:D
     
  7. Frankfort MB's

    Frankfort MB's Well-Known Member

    I recommend the Hobart BYOF
    :):p

    The 212 is so big I don't think there is a frame out there that it will fit in w/o modifications

    My bikes frame DEFINITELY isn't pretty too look at but I built it too get the job done so looks don't matter to me:D
     

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  8. Milkshake

    Milkshake New Member

    I guess ill try the 79cc. Cause that would impress the ladies lol :D:rolleyes:;)
     
  9. Frankfort MB's

    Frankfort MB's Well-Known Member

    Well the ability to burn the tires off a bicycle is pretty neat:)

    At least to the ladies around here:p
     
  10. Milkshake

    Milkshake New Member

    I was looking on eBay and I found this Ducar Clone Engine 196 CC. It looks kind of smaller than the Harbor Freight 212 CC I wonder if I can use that instead 6 and a half horsepower
     
  11. bakaneko

    bakaneko Active Member

    It looks like this guy has fairly detail videos of his 79cc Predator build. He is still working on it so more videos to come (1-3 thus far). Take a look it might give you some ideas.

     
  12. Frankfort MB's

    Frankfort MB's Well-Known Member

    I wish you good luck!!
    I'd like to see how your build compares! I'm sure it will look better than mine:)
     
  13. butre

    butre Well-Known Member

    predator 212s do fit felt el guapos and maybe bixbys, and I know there are a few dyno frames that they'll fit in, but for the most part you'd be building your own frame.

    you could maybe put it in the frame backwards and use a set of gears to reverse the rotation, sort of like happy time engines do, except on a jackshaft instead of built in.. this is something I've considered doing with a predator but just haven't had the time or money to do so. this method has it's pros and cons of course. pros being that the frame doesn't need to be so big, you can get some more of the gearing out of the way on the jackshaft, and the head of the engine doesn't point directly at your nether region. cons are added weight, cost, complexity, and parasitic power loss. I think there not being a piston flying at your junk at 300 miles per hour far outweighs the disadvantages.

    I mean, not that I've ever heard of a piston shooting out of the head, but that would feel a bit like a .30-06 point blank straight into the testes, and I'm not taking any chances.
     
    Last edited: Aug 4, 2016
  14. Frankfort MB's

    Frankfort MB's Well-Known Member

    i feel ya.... That's why I'm going to try to move the seat post around.....

    Here's a pic of me sitting on bike as of yesterday:D
    Wee bit close.... Wee bit too wide.... All things that can be fixed with a little bit of welding and cutting:p

    (Exact reason why I called my bike a Hobart BYOF.... I'm having to cut and weld so much on my frame it feels like i should have just built the thing from ground up..... It's still an all orginal 50's JC Higgins;))
     

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  15. bakaneko

    bakaneko Active Member

    can you show us how this is done or examples? im curious
     
  16. Frankfort MB's

    Frankfort MB's Well-Known Member

    It seemed to work well in my head but that's just me:)
     
  17. butre

    butre Well-Known Member

    I suppose you could also do a twisted belt for the same effect as the gears and omit the second jackshaft. would be cheaper, but with that much parasitic power loss you may as well just go with a china girl
     
  18. butre

    butre Well-Known Member

    I just attempted to confirm this theory and now I need a new belt for my drill press. might work better with a flat belt than a v belt. the thing was about ready to go anyway
     
  19. bakaneko

    bakaneko Active Member

    butre, what do you think of this. keep in mind we still gotta figure out solid mounting and gear ratio if this works and the advantages outweigh the disadvantages. if we place another sprocket above and slightly to the right of the drive sprocket/clutch sprocket, only utilize the downward force of the clutch sprocket, and then drive this to the free wheel, we can utilize the right directional force to drive the free wheel sprocket CCW with a CW clutch sprocket. hopefully, i didn't goof up the directional force here...
     

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  20. Frankenstein

    Frankenstein Active Member

    What are the overall dimensions of that 212? I gots me an idear lolauahololalollz
     
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