What do to first

Discussion in 'Performance Mods' started by Dakota123, Sep 12, 2014.

  1. Dakota123

    Dakota123 New Member

    I just picked up a stock 49cc engine on a bicycle the other day. Dont know much about these little guys. Want a little bit more power out of it. What would be the first thing to upgrade that would give me the most benefit?
     

  2. butre

    butre Well-Known Member

    spark plug and wire. you won't go any faster but it'll make it run a lot nicer. a good expansion chamber is next on the list
     
  3. Ratty Natty

    Ratty Natty New Member

  4. Dakota123

    Dakota123 New Member

    Any good companies to look at for the expansion chamber or does it really matter? And what size gap for the spark plugs are the best?

    Heres a pic of my bike
    [​IMG]
     
  5. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Looks like a 66 cc but your bike is too small in the pic. Seriously, we don't need to see that tree? :grin5:

    Gap plug at 0.028
    NGK B7HS or B8HS

    Your fuel filter is backwards.
     
  6. Dakota123

    Dakota123 New Member

    [​IMG] lol is my fuel filter really backwards ?! And how can you tell if its 66cc? Thanks for the info on the spark. Where can i find the wires for it? Would napa have it?[​IMG]
     
    Last edited: Sep 13, 2014
  7. wheelbender6

    wheelbender6 Well-Known Member

    I liked the wider photo with the rails and nice hard wood tree. Seeing it was like a mini vacation for me.
    I agree that exhaust and ignition are great first performance steps.
    Sickbikeparts.com makes a nice expansion exhaust.
     
  8. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    Closer up pic says it is a 48cc
    Your CDI has a soft boot that takes the spark plug with a terminal and really doesn't need upgrading.
    All the motor kits I sell come with it now.

    Yes, your fuel filter is backwards. Look closely and you will see an arrow on it.
     
  9. Dakota123

    Dakota123 New Member

    Haha ok ill change that. As for the expansion chamber is there any way to get one that angles down the same way? Or you gotta heat it up and bend it how u want
     
  10. Dakota123

    Dakota123 New Member

  11. velzie

    velzie Member

    Im almost certain tthe banana exhaust pipe would NOT fit between your down-tube and front wheel. Check the kind of clearance bikes have with that exhaust and you'll see a much larger gap.
     
    Last edited: Sep 14, 2014
  12. Dakota123

    Dakota123 New Member

  13. butre

    butre Well-Known Member

    those fit anything the stock muffler fits but I would personally get an arrow torquer II.

    anything that exits out the bottom does nasty things to ground clearance and makes you smell like exhaust fumes after about 2 minutes of ride time
     
  14. Dakota123

    Dakota123 New Member

    just threw on a new spark plug and it runs a lot smoother but the idle is still high whats that lever on the carb do? if i push it up the motor cuts outs and it doesn't seem like theres any in between. If i tighten the idle screw will that raise the idle?
     
  15. velzie

    velzie Member

    THe lever is the choke. It lessens the amount of air going into the carb and is usually only for starting the motor. tightening the Idle screw will increase the amount of air/fuel mix going through the carb and will raise idle speed. Open up the carb and take a look. Also read about carbs. there is a great sticky for that
     
  16. Dakota123

    Dakota123 New Member

    Well i just took it out and when the choke lever is down [​IMG]

    the bike revs out. And when i put the lever "up" it cuts out.
    When the lever is down and i adjust the idle screw it doesn't seem to do anything at all
     
    Last edited: Sep 15, 2014
  17. velzie

    velzie Member

  18. HeadSmess

    HeadSmess Well-Known Member

    too true...even with an exhaust over 12" behind ones rear end, the fumes "suck up" into the low pressure zone created behind you as one travels along... every head check becomes a deep breath of lovely 2 stroke exhaust :)

    meh. all pipes available for sale are mere gimmickry, fancy, chrome plated, chinese trash, compared to real, properly designed tuned pipes...

    they do something, but not much. mostly make more noise.

    im happy to sell my collection of pipes ive made over the years now the motorised bike is banned... 5 at last count... but shipping to US from here (AU) is gunna be the biggest expense!


    get a frame with some real brakes on it!
     
  19. Fabian

    Fabian Well-Known Member

    A 66cc top end
     
  20. Fabian

    Fabian Well-Known Member

    Won't be long before motorised (internal combustion engine) bicycles are completely banned in every state and territory in Australia.

    The ramifications of such laws are totally draconian, because police will have the power to confiscate the bicycle and throw it in the impound centre. The cost of getting your bike out of the impound centre is $800, plus the cost of tow truck fees to take it there.

    Then you will face fines for an unregistered vehicle, which in Victoria is $1000, and that's just the start of the fines. It gets a heck of a lot worse if you don't have a motorcycle licence or you are disqualified from driving.
     
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