KTM 50cc engine on bicycle

Discussion in 'DIY Home Built Motorized Bicycle (non kit)' started by BlueSmoker, Aug 23, 2016.

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  1. BlueSmoker

    BlueSmoker New Member

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    I am thinking of buying a KTM 50cc engine clone from 2005, to my bicycle.
    Do you know how sutainable they are? They seems to be as strong as modern trimmed moped engines, around 9hp. I would like to have an engine that is strong and sutainable. Do you know how mutch fuel they are drinking? If i am right, they do not have any gears, so what do you think? Do i need to ride at high RPM if i want to ride in about 35-40 mp/h if i ride with a 32 tooth sprocket or maybe even smaller?

    Is there any better engine i could use instead? Some Morini engine maybe?
     
    #1 BlueSmoker, Aug 23, 2016
    Last edited: Aug 23, 2016
  2. maniac57

    maniac57 Old, Fat, and still faster than you

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    Yes to all your questions.
    KTM engines and clones are good quality engines.
    They are ALL high-rpm screamer type engines which need to rev to make good power.
    They come with a centrifugal clutch that requires lots of tuning and maintaining, most people replace the stock clutch with aftermarket unit ($250+ & up)
    It drinks a lot of fuel because it makes a lot of power
    It will require top notch skills to fabricate a good mounting system and top quality parts on the bike.
    Huffy AIN'T gonna cut it.
    Morini is the same but Italian, so parts cost triple.
    Not for beginners


    From the tone of your post, I would suggest a four-stroke for dependable, problem free riding.
    Get a 212 if you want real speed.
     
  3. culvercityclassic

    culvercityclassic Well-Known Member

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    I agree with this post.... Never been a fan of that hi rev motor...
     
  4. BlueSmoker

    BlueSmoker New Member

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    Okay, but does it drink more fuel than the chinese 66cc on same speed, or does it need more rpm for same speed? And how do you think it is if i use a 30 tooth sprocket? Do i need to ride at the fuel slurping screaming level if i want to ride in about 30/40 mph then? I don't want to need to fill my only 2l gas tank all the time with the expensive fuel.
    But how good is it for engines to be ridden heavy, thus fast but with low rpm? Does it overheat when it is air cooled maybe?

    And then, what do i really have to do with the clutch? is it something expensive?
     
    #4 BlueSmoker, Aug 25, 2016
    Last edited: Aug 25, 2016
  5. maniac57

    maniac57 Old, Fat, and still faster than you

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    Ktm needs to rev to about 10k or so.
    It drinks MUCH more fuel than any chinadoll because it makes 10 times the power
    It does NOT like to be lugged. I'd suggest more like a 50tooth rear depending on clutch/pipe/etc
    It does not overheat.
    The clutch is finicky and inconsistent. Most people replace it with racing unit like Cheetah.
    http://www.bmikarts.com/Cheetah-Racing-Clutch-from-Noram-_p_739.html
     
    #5 maniac57, Aug 27, 2016
    Last edited: Aug 27, 2016
  6. BlueSmoker

    BlueSmoker New Member

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    Okay. It seems to be too expensive for me so i will probably let it be. But is there another better engines that i could use instead of chinese 66cc? I don't want any 4-stroke.
     
  7. Chaz

    Chaz Active Member

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    I can't think of any options that don't have a centrifugal clutch and don't require elaborate mounting.

    The new generation of the chinese engines have balanced cranks and better built than the older ones. But you need to buy from the right dealer. There's no reason you couldn't build up one of these with some after market quality parts to make it more reliable and more powerful. You can get the speed you want quite easily.

    I would advise to save the headaches and the money.
     
  8. mat_man

    mat_man New Member

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    CB2 likes this Mitsubishi clone:

    2 stroke engine - multi purpose 50cc with clutch and carb tool ($85)

    http://www.ebay.com/itm/2-stroke-en...d=100013&rk=1&rkt=28&mehot=pp&sd=131191973739

    He has done a recent build with this motor.

    I like 50cc and larger, 1970's chainsaw motors in good shape for $20.
    Beefier construction, more low end torque than the newer stuff.
    Much less expensive.


    Best are the 3-5 hp snowblower motors. Not any in the hot south, and I hate to pay
    ebay prices. Tecumseh and Jacobsen motors are most common.
     
    #8 mat_man, Aug 31, 2016
    Last edited: Aug 31, 2016

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