Top Speed, 80cc Chinese motor? what is the record?

Discussion in 'Motorized Bicycle General Discussion' started by scottcason69, Apr 26, 2013.

  1. SpecializedMountainMoto

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    Why not just put a nice rock shox air unit on there, it's a 1-1/8 head right. Depending on how much u spent it might have been way cheaper
     
  2. mapbike

    mapbike Active Member

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  3. Davezilla

    Davezilla New Member

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    When I was doing my top speed runs I noticed it didn't matter if I was upright or ducked way down, the speed was about the same, but I think the engine is rpm limited due to the rather small carb and just won't go past that rpm under load... I got a 20mm Tilly carb I want to try out to see if it'll go fastrer on top and I'm pretty sure it'll give a nice midrange and top end power boost as well.
     
  4. Davezilla

    Davezilla New Member

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    My first pipe was an old pocketbike pipe and it did let the bike accelerate very nicely but top speed was in the high 20's the pipe's outlet was just a hair bigger than the stock pipe's, the KTM pipe's outlet is almost an inch wide... bigger than the original header pipe...
     
  5. SpecializedMountainMoto

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    Yep that the one even about the same year I believe, mine was off a 2008 I think, I even paid about that exact price with free ship.
     
    #105 SpecializedMountainMoto, Jan 22, 2015
    Last edited: Jan 22, 2015
  6. Davezilla

    Davezilla New Member

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    Ok.. I just had to look and sure enough I got a pic of the bike with the pocketbike pipe I made foor it... it was nice and torquey but didn't have a very good top speed, this pipe cracked on me so I used the KTM pipe before I was ready to... but now that I got most the kinks worked out it's running really nice on the KTM pipe now.

    [​IMG]
     
  7. Davezilla

    Davezilla New Member

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    Mine came off a 2013 KTM, I got it cheap because it was dented, but I was able to hammer the dent out when I cut the pipe open to modify it... it's a bit more dented now tho because I needed to squeeze it slightly oval shaped so it would fit between the frame and the cranks... luckily it didn't effect power that much, just made it ugly... lol
     
  8. SpecializedMountainMoto

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    Yeah my pipe was way smaller than that, it's the one they sell for motorized bike but does not fit at all. Very small dia piping and tiny chamber
     
  9. mapbike

    mapbike Active Member

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    Yep if she is starving for a drink at high rpms your gonna be limited, kinda like a 406 Small Blocjk chevy I built years ago, it would run with a little 1850 600cfm holley vac secondary carb, but when I stuck the old 7010-1 780cfm dual line on it it came alive.

    When the engine needs more air and fuel there just isn't a substitute.
     
  10. Davezilla

    Davezilla New Member

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    I think I know which one you're talking about... not the banana pipe but the one that's basically a header and has a cone facing the inlet and outlet but no belly in the middle, then maybe a muffler on the end? If it's that one, yes, those are very restrictive... The banana pipe is restrictive too but also tuned so it needs more rpm than one of these engines could spin anyway...
     
  11. Davezilla

    Davezilla New Member

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    Same thing I did on a 302 I put a Holley 750 vacuum secondary on, all my friends told me the 750 was way too big for such a small engine, but it woke up really well with that carb and I actually gained power even down low.
     
  12. SpecializedMountainMoto

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    It was this pos I had,
    http://m.ebay.com/itm/231236992549?nav=SEARCH
    For some reason they jacked the price about 100.00 got mine for 30.00 and it's useless except for the rear portion with the bracket for the seat post clamp. That part worked out very well with the kx65 for holding the weight.
     
    #112 SpecializedMountainMoto, Jan 22, 2015
    Last edited: Jan 22, 2015
  13. SpecializedMountainMoto

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    "The FAST expansion chamber" hahaha what a joke
     
  14. SpecializedMountainMoto

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    I see a lot of people asking about this pipe and hopefully they see this thread
     
  15. Davezilla

    Davezilla New Member

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    Yup... that's the one I was thinking about... there's just no room in that little chamber and they rely solely on the header length to tune it and the powerband is pretty narrow too so it's pretty useless, maybe just enough for someone to say they got an expansion chamber on their bike...
     
  16. Davezilla

    Davezilla New Member

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    Haha.. Very nice... You'll definitely feel a difference once you get it welded up to fit... just try not to add or take away too much length when trying to make it fit, this one gives a nice wide powerband tho so if ya have to add or take away an inch or 3 it won't hurt it too bad, bot 6" to a foot could push the power out of your engine's range... that's part of the reason mine has a few extra bends in it, but it was also coming on too late so I added 4" to the belly... the 65cc pipe you got should be near perfect and keep the power where it is now... but just more of it.
     
  17. mapbike

    mapbike Active Member

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    I've got one of those exact pipes still in the box, I think I paid about $40 for it, it might be a little better than a stock exhaust but def not a performance exhaust for good rpm and top speed power.
     
  18. SpecializedMountainMoto

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    Yes u should not have to even modify this pipe at all, I did not. It comes around the front of the down tube nicely and then resides on the right side. U will need to extend the end a little like I did so you can support the weight, the seat clamp works great
     
  19. SpecializedMountainMoto

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    Oh great then I would recommend cutting the rear off and doing it how I did onto the kx65
     
  20. mapbike

    mapbike Active Member

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    I might rig this up on my Kulana bike since I already know how it runs with the pipe I have on it now, this bike has seen upper 40's on the flat but not since I put the current exhaust on it.

    that is Kx65 pipe will most likely get it to running better again and sound better also.
     

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