Pedal-less acceleration?

Discussion in 'Motorized Cruiser Bicycles' started by motorizedinDC, Sep 8, 2016.

  1. motorizedinDC

    motorizedinDC New Member

    Joined:
    Sep 8, 2016
    Messages:
    1
    Likes Received:
    0
    Hi,

    Would there be a way to modify the bike in such way that my motorized bicycle would accelerate without a pedal? I have come up across too often when I could not accelerate on uphills after stopping at a red light or stop signs. I had always walked my bike to a flat ground or downhill for it to catch enough speed to accelerate.

    My motorized bicycle has a 49 cc on a huffy bike. It's pretty heavy :-0

    .shft.
     
  2. ZipTie

    ZipTie New Member

    Joined:
    Jan 8, 2016
    Messages:
    637
    Likes Received:
    2
    Not really, other than adding a huge rear sprocket like a 54 tooth, adding a reed valve, expansion chamber, porting. If you did all of these changes you might be able to tackle bigger hills because you would be adding so much more low end torque. But with the big sprocket you will also give up speed. These 2 strokes really need high rpms and flat ground to get a running start at hills. Cheapest thing to try through is the huge rear sprocket to add that low end slow grunt. Hope this helps.
     
  3. ZipTie

    ZipTie New Member

    Joined:
    Jan 8, 2016
    Messages:
    637
    Likes Received:
    2
    Also/ the 49 cc just has a bit less horsepower as you know so an up grade to a 66 cc for a bit more grunt. I have never used a 49 cc engine, I do hear they run very smooth though.
     
  4. Ghost0

    Ghost0 New Member

    Joined:
    Mar 7, 2008
    Messages:
    764
    Likes Received:
    0
    Well there is such a thing called a Shift Kit allowing you to use the gears on the bike so that one could have a low gear for acceleration and taller gears for cruising at higher speeds without over revving the engine. Of course if you have a typical beach cruiser that is a single speed that's not going to work.
     
  5. Bruce Lee

    Bruce Lee New Member

    Joined:
    Dec 13, 2010
    Messages:
    46
    Likes Received:
    0
    79cc 4 stroke
     
  6. Ghost0

    Ghost0 New Member

    Joined:
    Mar 7, 2008
    Messages:
    764
    Likes Received:
    0
    The kit is not designed for the 79cc engine but some have made it work from what I have been told.
     
  7. WECSOG

    WECSOG New Member

    Joined:
    Nov 10, 2014
    Messages:
    114
    Likes Received:
    0
    Another vote for the shift kit. If I go 4 stroke I doubt it will be some dinky 79cc thing.
     
  8. QuietRiot522

    QuietRiot522 New Member

    Joined:
    Aug 31, 2010
    Messages:
    60
    Likes Received:
    0
    I have a centrifugal clutch kit on my 66cc and I love it. I just have to kick off with my feet at a stop and ride the gas as I move my feet back on the pedals. Still need to give a couple pedal turns to get up to speed but, its still so much easier than pedaling then dropping the clutch. Doesn't work on really steep hills but most occasions it has made my riding experience better. Something maybe to consider. Maybe a clutch + a bit of a gear reduction would work to get you taking off at the bottom of hills with less effort.
     
  9. mogollonmonster

    mogollonmonster New Member

    Joined:
    Aug 26, 2015
    Messages:
    468
    Likes Received:
    0
    High compression head, adjust port timing to match (can be done with gasket thickness under jug), expansion chamber and proper jetting. Oh and like ZipTie said, get the bigger motor, there is no replacement for displacement. A change of gear ratio might help, but it doesn't change the fact you need more power. Proper jetting also helps, you shouldn't be fourstroking climbing a hill, maybe on the flats or going downhill, but it should smooth out on any kind of grade, two smokers like to be a little rich under load. A bigger rear sprocket might reveal the need for leaner jetting. Its good to know how to do, and very easy.
     
  10. Wild Bill

    Wild Bill New Member

    Joined:
    Jan 29, 2013
    Messages:
    478
    Likes Received:
    0
    Another vote for shift kit, I built 2 bikes with them, one runs a KTM 50 engine and they make for great street riding without pedaling.
     
  11. Agreen

    Agreen New Member

    Joined:
    Feb 10, 2013
    Messages:
    784
    Likes Received:
    1
    Hybrid sounds like what you want. Gas rear wheel drive, electric front wheel drive. If all you use it for is take-off assist, you don't need a massive battery.
     
  12. ultralight01

    ultralight01 New Member

    Joined:
    Oct 30, 2016
    Messages:
    338
    Likes Received:
    0
    Hybrid is cool but heavy.
    Try a predator 79 or 212.

    EDIT:, Sorry, accidental reawakening of a dead thread.
     
    #12 ultralight01, Dec 19, 2016
    Last edited: Dec 19, 2016
  13. Tyler6357

    Tyler6357 Member

    Joined:
    Mar 15, 2012
    Messages:
    748
    Likes Received:
    1
    Put on an expansion pipe with a long header so you get more low end.
     
  14. KCvale

    KCvale Active Member

    Joined:
    Feb 28, 2010
    Messages:
    3,797
    Likes Received:
    2
    Is this a 2-stroke or a 4-stroke?
    48cc and 66cc is typically 2-stroke, 49cc and 53cc are typical HS 4-stroke engine sizes.



    Save
     
  15. sbest

    sbest New Member

    Joined:
    Nov 3, 2015
    Messages:
    340
    Likes Received:
    0
    I'm with Mongo.
    I have a 49cc two stroke. With very little work it will pull away from a dead stop and do hills.
    1) Use a 54 tooth back sprocket
    2) improve the head by adding a bit of squish and compression.
    3) bring the new-found squish to 0.5mm to 1.0mm by adjusting head and base gaskets
    4) drill the exhaust flange and gasket with a 3/4" (19mm) drill
    5) jet the main by plug chops and the needle by performance.
    6) widening the top of the exhaust port will help too, but don't raise it.
    7) a longer intake tract or filter will help too

    Even the 49c will pull away with these mods done right.

    Steve
     
  16. racie35

    racie35 New Member

    Joined:
    Nov 17, 2012
    Messages:
    1,698
    Likes Received:
    0
    I guess this is directed at the China girl bikes..I know my whizzers don't need help , but one of them is pullied smaller on the clutch to wheel helping that one. The stock wc1 though, hardly struggles if you use its manual clutch right.
     
  17. KCvale

    KCvale Active Member

    Joined:
    Feb 28, 2010
    Messages:
    3,797
    Likes Received:
    2
    Hey Steve, where did you get your 49cc 2-stroke?
    Every one I have worked with is 48cc.
    The thing is, 49cc is a valid size for 4-stroke but not for a 2stroke and why I asked if he had a 2 or 4 stroke.

    I'd just like to know who is faking the 48cc number and folks like you buying the 1cc claim is all.
    It's not as bad as the 66/80cc scam, but enough to be annoying in topics like this.
     
  18. LandSpeedRecord

    Joined:
    Dec 11, 2014
    Messages:
    604
    Likes Received:
    0
    A properly ported and set up 66cc will pull you strong right off the line and up to about 43mph with the stock 44 tooth kit sprocket. If you want more, a real expansion chamber, higher flow air filter, better plug wire & booth, and really seal up the carb, intake, etc from all the tiny vaccuum leaks. If you get it right you will blow by shift kits and keep going. They very much have thier place in high end comfortable to ride at a much lower cruising RPM builds but for performance, simplicity, and dollars you won't get close to a high quality 66cc. I have countless hours with the best kits SBP offers and I love them and even use their 4 stroke mount in non shifting builds.
    The short answer, if you want to pull off the line and reach any reasonable speed a 66cc kit from DAX, CRmachine, me, whoever will build you a proper one will outperform anything else short of spending a ton of money.
    If you have the money to drop a 53cc shifter bike by KC will pull you right off the line I bet real well AND be the nicest to ride but you have to drop the dollars.
    The best thing I have found with the 48cc bikes is they are already motorized so it's quick and easy to yank the 48 out and drop the bigger motor in lol.
    All just my opinion.
     
  19. sbest

    sbest New Member

    Joined:
    Nov 3, 2015
    Messages:
    340
    Likes Received:
    0
    Yeah, yeah, yeah, I'm busted...
    THOUSANDS of numbers floating around in my head and I messed up.
    And you are right KC, it is important.
    I mean, who would drive a 352 Chevy? or a 288 Ford?
    I humbly submit to public flogging... <SHAME>

    Steve :)
     
  20. KCvale

    KCvale Active Member

    Joined:
    Feb 28, 2010
    Messages:
    3,797
    Likes Received:
    2
    Hehehe Steve, I just thought maybe there was something new I didn't know about is all ;-}



    Save
     

Share This Page