Which engine is more balanced?

Discussion in '2-Stroke Engines' started by adb140275, Aug 11, 2010.

  1. adb140275

    adb140275 Member

    I'm looking at getting an engine kit for one of my bikes, and im wondering which engine is more balanced (vibrates less) between the two im looking at. my friend has this one http://www.gasbike.net/bicycle_motor_engine_kit_gas_bike_jet_80cc.html and it vibrates like **** over 25mph, and i had to ride it 4 miles to his house for him...
    So i was looking at this kit instead http://www.gasbike.net/grubee-skyha...otor-kit-black-finish-bicycle-engine-kit.html and im wondering if its a better balanced engine...
    Last edited: Aug 11, 2010

  2. motorpsycho

    motorpsycho Active Member

    they are the exact same engines with the exception of the slant head.
    the slant head has a little more compression and the angled spark plug is good for clearance issues.

    vibration has little to do with how these engines are balanced...it has alot to do with how the engine is mounted to the bike.
    I have one bike that does not vibrate at all, and another bike that has mild vibration around 25-28 mph.
    2 different style frames, 2 different engine mounting methods.
  3. GearNut

    GearNut Active Member

    I have read on the forums that all of the engines have a crank shaft that is balanced for 60cc. I have also seen photographs showing how the counter weights were assembled wrong on the crankshaft from the factory.
    If you want smooth I guess you want a 60cc and a good vendor.
    These engines are like a spin of the roulette wheel. Will it be a good one or a lemon?
    That is why you want a good vendor, one that will warranty a lemon without hassle.
  4. Bobbyoutback

    Bobbyoutback Member

    Hi Gearnut , like reading your posts , I know a vendor that sells a 58cc , they say its as powerful as the 66cc & a much better motor :thinking: , your opinion ?

  5. GearNut

    GearNut Active Member

    I suppose that it depends on the vendor. Do they have a good reputation for honesty and excellent customer service/ warranty response?
    Or do they have an overstock of 58cc engines and are willing to advertise with marketing spin to get them out of the door.
    I really do not see how a smaller displacement engine can match the output of a larger engine without performance upgrades, unless we are talking Morini versus Happy Times. Morini being a flat out better design from the get go.
    Just speaking 58cc HT versus 66cc HT, The 66cc should be more powerful.
    Now for the variables: There are a few factories that make these HT type engines. Some are better with quality control that others. A higher quality 58cc could definitely out perform a lower quality 66cc.
  6. motorpsycho

    motorpsycho Active Member

    i have one engine that is supposed to be a 49 c.c., and another one that is a 66 c.c. (80)
    they are both h.t. style engines, but the 49 c.c. is designed a little different than the typical 66 c.c. the 49 c.c. has no intake tube, (carb. is bolted right to the cylinder) a different style carb. regular nuts holding the head on (not the acorn style nuts), a square looking cylinder, and a slant head.

    here is exactly what the sticker on the side cover says on my "49" c.c. engine:
    date of mfg. Feb. 2009
    This engine conforms to 2009 U.S. EPA
    regulations for small non-road engines.

    now, i just bought a 66 c.c. engine that is a typical h.t. engine with the intake tube, acorn nuts on the head, a more rounded cylinder, and a slant head.
    here is exactly what the sticker on the side cover of this engine says:
    date of mfg. sept. 2009
    This engine conforms to 2009 U.S. EPA
    regulations for small non-road engines.

    the sticker from the "49" c.c. engine is yellow, while the sticker from the 66 c.c. is blue, but they both say the exact same thing other than the date of mfg. and the serial #.
    these engines have the same amount of power and they both run very well (but i did some tuning on both of them)
    so...when you buy a "49" c.c. engine are you actually getting a 66 c.c.? has everyone noticed that 49 c.c. 2 stroke h.t. style engines are prtty tough to find these days? could it have been a way to lure people in to the hobby for a little less money? thinking they were getting a smaller 49 c.c. engine, when in fact they were getting 66 c.c. engines at a cheaper price?
    the only way to tell is to tear it apart and measure everything, but i'm not going to do that.

    or, is it just that I got what I got, and the vendor I used was selling slightly different looking 66c.c. engines saying that they are 49 c.c.'s?
    i don't know but both of my engines run the same and they both feel like they have the same power. both of my bikes have 41 tooth sprockets on them, and modified exhausts.
    Last edited: Aug 12, 2010
  7. Bobbyoutback

    Bobbyoutback Member

    Here is the link to that 58cc kit , notice how expensive it is !
  8. GearNut

    GearNut Active Member

    I know that things cost more in Australia, but good lawd! That's expensive!
    There are a few folks here that hail from Australia. Perhaps they can steer you to a better, cheaper, more customer friendly vendor.
  9. motorpsycho

    motorpsycho Active Member

    it looks like a typical h.t. engine kit to me, but it looks like comes with a heavy duty rear hub, drum brake, and a cheap plastic gear driven speedometer that will not last (i know...i had one).

    if you watch the video, they never mention a 58 c.c. engine, they mention, a 48 c.c. kit, a 55 c.c. kit and a 66 c.c. kit. the e-bay auction is for a 58 c.c. engine kit.
    so where is the 58 c.c. engine in the video?
    Last edited: Aug 12, 2010
  10. Bobbyoutback

    Bobbyoutback Member

    Hi Guys ,
    I will stick with my old 66cc bikes , I run 56tooth back sprockets for the low down power as they are only used out bush for prospecting .

    Motorpsycho your right about that discrepancy of 58cc being 55cc , gee that annoys me when these motors CC's are quoted wrong :annoyed:
  11. geebt48cc

    geebt48cc Member


    :grin5::ack2:........................Well, doing legal stuff with 48cc........................

    It gets you there..................but.............................top end is 33+

    level uno.....................

    PS-I'm 250lbs........................6' 7"
  12. GearNut

    GearNut Active Member

    You need a Morini !