The Pocket Bike Engine and Your Opinion...

Discussion in 'Motorized Bicycle General Discussion' started by conradcliff, Nov 13, 2008.

  1. xPosTech

    xPosTech The Old Master Motorized Bicycle Builder

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    The roll your own wheel motors use very little torque to turn the wheel. 36 magnets around the rim and DIY wound coil. A 36 pole motor/alternator gets into some high frequencies, esp. at speed.

    To give you an idea of rotor diameter vs. torque, turn your wheel from a spoke crossing near the axle, then turn it from a spoke near the rim. That's the difference in torque the motor "sees" or has to overcome. A hub motor vs. a wheel motor.

    By ICE, I thought you meant Internal Combustion/Electric. I was exposed to the wheel motor (actually alternator) watching a Discovery channel bit about green vehicles and human power generation. The guy on there only used four magnets on his wheel to power his lights and GPS. But why stop at four?

    I'm gonna have to look into this.

    Ted
     
  2. mechanickid

    mechanickid New Member

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    you we're right, i asked him.
     
  3. europorsche914

    europorsche914 New Member

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    seems like the consensus over on pocketbikeplanet is for us to stick with what we got and just fit reed valves and bump the compression to 10+:1...
     
  4. Weedylot

    Weedylot Angry Old Fart

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    Techno, Those motors look mean. I'd be wanting a sturdy bike for that bad boy.
     
  5. europorsche914

    europorsche914 New Member

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    yea i got a custom reed valve setup that i posted info on a but i havnt had time to tune it... it runnin the same carb pipelyne is runnin on their reed valve setup. im gonna look into what i can do to bump compression on my motor, install SKF bearings (got a deal at 4 for $16) and balance my crank during Thanksgiving break from college... Ill let everyone know what happened...
     
  6. Technocyclist

    Technocyclist Motorized Bicycle Senior Technologist

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    I'm still looking for a frame for this. Probably a chromoly or steel BMX or Cyclocross frame.
     
  7. Technocyclist

    Technocyclist Motorized Bicycle Senior Technologist

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    Hey guys, do you really think the crankcase, pistons, and barrel on the chengine could really handle the RPM and power when reed valves are installed, and porting is done. The crankshaft is not balanced, and is offcenter. How do you plan to reinforce the structural integrity of the chengine? and balancing the crankshaft?
     
  8. Technocyclist

    Technocyclist Motorized Bicycle Senior Technologist

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    #48 Technocyclist, Nov 21, 2008
    Last edited: Nov 21, 2008
  9. conradcliff

    conradcliff New Member

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    Dang! There have been a ton of replys to this thread..glad I made it ^5

    I'll be ordering my parts next week, I'll keep you all informed on my progress.

    Techno, I had stumbled across thos engines as well and was drooling over them..just make sure you've got a tough bike! I plan on reinforcing the rear mainstays on mine with some channel iron and I don't even have 4hp...

    Thanks for all the discussion guys, let's keep it coming! (^)
     
  10. conradcliff

    conradcliff New Member

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    Ok, so I've ordered all the gearing and the freewheel crank setup but I got spooked by one of the guys over on the pocket bike forum I joined about the reliability of these engines..anybody have any first hand experience with them that can attest to how reliable they are?
     
  11. curtisfox

    curtisfox Well-Known Member

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    Where do you get the 3 speed transmission from?
     
  12. old motorbike

    old motorbike New Member

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    I really like this engine concept, but it's just too wide for pedals. Isn't that the requisite for a motorized bicycle?
     
  13. junkyard

    junkyard New Member

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    well i just had to join so i could reply

    i probly cant post pic til i post enuff times but i have a schwinn spoiler with a pocket bike motor on it... i made the 'kit' myself from stuff from ebay

    its been a few yrs since i built it and i dont really ride it because i got rid of the pedal drive so i could keep the rear disc brakes and now it just has foot pegs

    first off the build went great and all the parts worked perfect and it goes atleast 40mph....havent maxed it out so im not sure....i got to 36mph and it was fast enuff for my first run and it had more to give......rode home doin 35 no problem

    but there are some issues.....like the no low end at all....i have to basically push off to get goin but its not too bad......good for long rides but terrible for in town

    i used the stock 7 tooth drive sprocket and went with an electric bicycle 90 tooth rear sprocket (pocket bikes have smaller links...about 44 tooth bicycle sprocket size approx)....i flipped the rim and screwed the sprocket right onto the rim then bolted it thru the hub flange.....worked beautifully

    i bought an alloy dirtbike throttle and a throttle cable for a mini chopper and a tank from a bike kit dealer and 5 foot of chain

    it worked really well because the rear tire of the pocket bike is 4" and the rear tire of the chopper is 4" so the motor is pretty centered on the frame

    made the mount out of scrap bike frames and parts from a tv satallite dish mount

    this motor mounts on the bottom with 4 bolts and has 2 bolts on the top that has another bracket above the engine......i just did the same thing with my mount

    hopefully i can post pics soon
     
  14. junkyard

    junkyard New Member

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    i guess i can post pics
     

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  15. junkyard

    junkyard New Member

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    a few more pics
     

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  16. junkyard

    junkyard New Member

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    btw im now planning on buying a kit and building a bike with one of those so this time i can keep the pedals....lol
     
  17. Dan

    Dan Staff
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    Very cool Junkyard
     
  18. Humsuckler

    Humsuckler New Member

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    i just want to bump this thread and add my .02.

    i thought about this a bit, and rack mounting the motor is the way to go due to the pocketbike engines measurements. it is cramped to get one in a bmx frame, i thought about that a year ago. however, here is the rack mount kit i think would be best for PB engines, and i am a member on pbp i will attest to their reliability. they are really really easy to work on plain and simple, and if you know what your doing with them they will last a long time. i have 3 years on one stocker and it still starts up first pull and runs great! they just wont gernade like HTs will.

    anyway, here is what i have found so far, i may not be eye pleasing but it works.
    Golden Eagle Bike Engines, Geared Belt Drive Bicycle Engines / Motors for Mountain Bikes & More

    i am still waiting to hear from them as far as if a pb engine will fit the setup, im sure it will. there are alot of GEBE fans on the "other site" ill ask them for a bolt to bolt measurement to compare with my pb engine.

    ON THE OTHER HAND HOWEVER.....

    im thinking, that it would be much easier to just buy a pocketbike as suggested, get it running, and cut it in half to make a pusher out of. you could then gear it for as much top end as possibble and probley get to 60kmh, which is exactly what im in the process of doing right now.
    http://motorbicycling.com/f3/sacrificing-pocketbike-push-trailer-10066.html

    i will put a picture up tomorrow.

    now for some good stuff,
    a stock pb engine without ANY mods really is a well engineered little powerplant, They are peppy, and the centrifigual clutch will pick up speed rather fast if you back off the throttle and reaccel a few times.
    remember, the centrifigual clutch slips, so to get up to speed, you have to release its grip and grab the drum again a few times before you have maximum speed.

    a modified pocketbike engine with stiffer clutch springs engages harder. the best bang for your buck as far as just an engine can be found on ebay.
    Mini Atv Quad Dirt Pocket Bike Big Bore Engine Parts !! on eBay.ca (item 290305868858 end time 24-Aug-09 01:02:33 EDT)
    ADA clone motor, dellorto rep carb, 2 shoe clutch. thats your basic upgraded high comp pb engine.
    oh, and my expert opinion like stated on pbp is that the pbu "race engines" are grossly overpriced. by about $300. so, you make the call there lol

    !lastly, they STILL wont beat a morini, but they sound the same and perform just as good, just different! ill be watching this thread!
     
  19. john_the_great

    john_the_great New Member

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    ENGINES
    here is one of the places I have found that sells pocket bike engines.

    I just have to throw my 2 cents in as well, these motors would probably work with a four-stroke like mounting system and wide cranks, they will go faster then the ht motors but put out ALL of their power on the top of the rev range making them either slow and zippy or fast with no acceleration. honestly I think that one of these motors would make the best performance upgrade, but need a transmission solution.
     
  20. Humsuckler

    Humsuckler New Member

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    it would be interesting to see if the ez-motorbike clutches would fit. i know the GEBE rack mount kit will fit a pocketbike.
     

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