GT50r - do not do it

Discussion in 'Motorized Bicycle General Discussion' started by douglasseattle, Aug 31, 2011.

  1. douglasseattle

    douglasseattle New Member

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    GT50r - (one model below) wait and see

    I purchased a model, which is the same motor, but one less horsepower. It is mounted on rear friction drive. My hope to have more power and reliability than the Happy Time motor on my other bike. It failed on both counts. The HT is far better on hills and is more reliable. The first time I rode this I got stalled 15 miles from home - no spark. The spark plug boot has a clip in kind of boot which had fallen apart. I got it going for about a minute then no more.

    As for hill climbing and top speed. With my HT motor I have it mounted on a old Univega hybrid bike with a fat tire on the rear. I top just over 40 with a front racing tire from my racing bike. It cilmbs quite well even though it has a 32 sprocket on the back.

    The gt50 tops out at 33 on a racing bicycle that is lighter and more aerodynamic. Hill climbing is poor! The motor is smoother however. I am hoping that break in will show dramatic hp improvement. We will see
     
    #1 douglasseattle, Aug 31, 2011
    Last edited: Sep 1, 2011
  2. lowracer

    lowracer New Member

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    douglassseattle,
    Not sure what was wrong with your engine?
    I got 2 similar Cag engines off eBay from Zero Pulse USA (Stage 2 Pocket Bike Engines) & they both needed new longer headbolts w/red loctite, copper base head gaskets (replace the paper ones), new spark plug (NGK C7HSA) & wires (using an 7mm automobile plug wire).
    Both are equipped with Pocket Bike expansion chamber pipes.
    These engines are very powerful & push both my bikes beyond 50 mph. I had a 98cc Lifan 2.5 on one of the bikes prior & this little engine has more go.
    Like the china girl engines, they do require attention & tweaking which to me is part of the fun of our hobby.
    Sounds to me like you aren't geared correctly. The Pocket bike engine needs a gear reducer to run a 32 tooth. I geared mine w/ 1.5" V-Belt pulley on engine & 22.5" wheel pulley (rim mounted to rim). I tried a 1.75" engine pulley & it wouldn't allow the engine to get into its powerband...Huge difference .25" makes...
    -Lowracer-
     
  3. donutguy

    donutguy New Member

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    I had a couple of the GT 50r's and I ended up returning them.

    I got one of thatsdax's 4 stroke motors......very happy with it.

    It's quiet and it has bags of low end torque.

    I'm not really to concerned with top speed....as long as I can go 20mph-I'm a happy boy.

    It climbs hills like a mountain goat :)
     
  4. kallsop

    kallsop New Member

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    I don't see the GT50R on the thatsdax web site any more. Hopefully there is something better coming.
     
  5. donutguy

    donutguy New Member

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    I have the newer version of thatdax.com's new 2 stroke. It's still in development.....but I have been using it on and off for the past week weeks. It's a pretty nice piece, but right now I have my new 4 stroker bolted up to my bike.
     
  6. gera229

    gera229 New Member

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    Hey donut guy, you ended up returning the GT50 dax engines? Why?
    Did you have the stage 2 kit on them?

    The newer one? What's the newer one? Is it the same engine? What's new?
    How is it different from the original GT50R engine?

    Thanks!
     
    #6 gera229, Sep 18, 2011
    Last edited: Sep 18, 2011

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