49cc vs 80cc questions on differences

Discussion in '2-Stroke Engines' started by wildone, May 30, 2015.

  1. wildone

    wildone New Member

    first off is there a difference in the stroke of the 49cc verses the 80cc i know the bore is not the same but what about the stroke on a stock motor set up???
     

  2. crassius

    crassius Well-Known Member

    I think stroke is same on the older models (some new 80s have diff stroke), but I haven't seen a 49 in many years. 49 is faster on flat roads (prob due to swinging less weight), but here where the hills are steep, only the 80s will climb them.
     
  3. The_Aleman

    The_Aleman Active Member

    Yeah, the small chinagirls tend to out-rev the bigger ones simply because of less rotating mass. They also don't have as many balance issues in general.

    The bigger chinagirl will make ~50% more torque simply because of displacement. This of course translates to roughly 33% more horsepower.
     
  4. wildone

    wildone New Member

    i just bought a 2011 model 49cc from my friend and he said he only rode it maybe 20 times but i cant get it going much faster than a idle after sitting for about a year i even changed carbs but it still would not pick up any speed so i pulled it off the bike and replaced it with a new 80cc using the new clone carb the bike runs great now so im thinking of putting a bigger bore piston and liner on the 49cc motor. thats why i m wondering if the stroke is the same.. the 35 bucks for parts is cheaper than a new motor and i might learn how to port the jug while i m at it if the parts will fit
     
  5. crassius

    crassius Well-Known Member

    never seen a big bore fitted onto a 49cc - tho some folks say they can do it

    your 49 is probably good and just needs something adjusted a bit - head gasket & ignition are common fails
     
  6. KCvale

    KCvale Motorized Bicycle Vendor

    You can't 'bore out' a 48cc cylinder and put a 66cc piston in it, there is no room.
    The 66cc's have fatter and wider apart head bolts to accommodate the fatter cylinder and won't go on a 48cc bottom end either.

    If you plan to re-use the 48, just do the basics first.
    Pop the head and check inside for damage and debris, check the head gasket, then use an actual torque wrench and tighten the head to 12# ~4# at a time.
     
  7. wildone

    wildone New Member

    well i guess ill look for some one with a couple of old 49cc barrels to experiment porting on them before i try it on a new one..And your rite about poping it apart to see what i can see..i suspect he burnt the piston or liner or both.. ill let ya know after i pull it down today. And last but not least by any means thank you guy you already save me some headache and put me farther up the learning curve than i was a while ago
     
  8. crassius

    crassius Well-Known Member

    if he has 6mm studs, I'd recommend 8# +/-2# for that torque
     
  9. wildone

    wildone New Member

    well sure as shooting the head gasket is showing signs of being blown. i should of known when i saw 6 washers on each stud it was a tell-tale sign of a pre-existing problem not disclosed at time of purchase (go figure) thats why he flattened the tires so it could not be riden.. never the less its a easy fix.. on to the next problem the air filter wont fit against the seat post down tube.. need to find a flex hose to fit the clone carb and build a air box
     
  10. wildone

    wildone New Member

    next question are the head gaskets reuseable on this motor ??? they dont look like they smash down like a exhaust gasket
     
  11. crassius

    crassius Well-Known Member

    if they're not pitted, I just turn them over to get a fresh bite
     
  12. wildone

    wildone New Member

    i bought a 12 volt generator from gasbike and when the thing didnt work i tried to contact them by phone after a couple of days i got thru to them only to be put off by the guy on the phone.. he said i have to talk to the guys in the tech department and he would have them call me between 11 and 2 the following day. what a bunch of bs that was i sat for two days thinking they would call but no way jose and trying to contact them takes forever...i was wondering about buying online or thru a shop.. now for certain i will never buy from gasbike again.. for the 31 dollars they are trying to screw me outta ill tell everybody that ask me about my bike to steer way clear of gasbike they are ripp offs...and in the proof they have themselfs to blame.. if they keep this up they wont be around long is my guess
     
    Coyoteloven likes this.
  13. dougsr.874

    dougsr.874 Active Member

    NEVER, EVER BUY from Gasbikes, Kings, or Zone 8 ..all the same company and they will screw you .
     
    Coyoteloven likes this.
  14. KCvale

    KCvale Motorized Bicycle Vendor

    gasbike/kings/8 are 3 different web sites for moving imported entire container boxes of Chinese MB parts as Nationwide Access LLC.

    In short the Amazon of MB parts already past customs and in the US ready to ship to you for cheap in a couple of days.
    They have already put in the millions to get a smooth pipe-line for the stuff we builders want cheap or at least available.

    Nationwide has been a crucial supplier for me for $100,000 worth of product so far.

    The 'trick' is to understand how difficult it is for a company just moving boxes to send something bad back to China and reimburse you, and having someone manning a phone all the time.

    Just use their customer service e-mail to request an RMA
    nationwideaccess@aol.com

    In short we all need to commutate facts faster and e-mail is a very efficient way for everyone.
    The business that sold you something may have no clue how what was in your box even works.
    The internet however likely does.

    Returning things that were clearly broken before install should be easy, but burdening a business with something you broke just so you don't loose is simply not fair and bad business all around.

    That said for all suppliers benefit, I have no love for Nationwide now that they lost the ability to supply Skyhawk parts and have lowered their quality of the main important things to the cheapest knock-offs they can find.

    A savvy shopper that needs no tech support is glad they around for all the 'little stuff' is all.
     
  15. wildone

    wildone New Member

    we all need to band together and boycott gasbike... wished i had known this before i bought from them in the first place
     
  16. butre

    butre Well-Known Member

    it should be noted that a 55cc cylinder will fit on a 48cc bottom end, but 55cc parts are the rarest china girl parts.
     
  17. KCvale

    KCvale Motorized Bicycle Vendor

    How about just You be the We All?

    They import like 50,000 different MB parts, I for one will not support some kind boycott to run them out of business because you can't handle an RMA bud, sorry.
     
  18. wildone

    wildone New Member

    you mean they cant handle a RMA bud..get the facts stright here... they were quick to take my money but dont honor any return and lied to me on top of it all.. you can take your chances but the smart money is on spending some where else like there competition so yes a boycott is in order
     
  19. The_Aleman

    The_Aleman Active Member

    That's like trying to boycott the warehouse that supplies every store in one's town.
     
  20. KCvale

    KCvale Motorized Bicycle Vendor

    Pretty much.
    Try and find any other US distributer that stocks most everything.
     
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