clocked at 38mph today

Discussion in 'Motorized Bicycle General Discussion' started by Xiodinc, Jul 23, 2012.

  1. Xiodinc

    Xiodinc New Member

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    Running my 66cc engine with custom pipe, 44t sprocket, clocked at 38mph today. pretty excited cause i still have a 36t in my house to put on it and i still need to rejet the carb and get an air filter for this baby. maybe a billet intake mani too.
     
  2. Xiodinc

    Xiodinc New Member

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    This is the only picture i have of it now.
     

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  3. young grease monkey

    young grease monkey New Member

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    Revving it that high will blow your top end very quickly. Lower gearing and more torque is better. Try a reed valve intake, the other intakes on the market don't really do much. Reed valves are one of the reasons 2 stroke dirt bikes put out so much power.
     
  4. Longshot270

    Longshot270 New Member

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    Police clocked you at 38 and you got away with it? Dang, wish I had that kind of luck.
     
  5. Pilotgeek

    Pilotgeek New Member

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    I did that once, except with a 41t sprocket. It was down a 1-2 degree incline with a 10mph tail wind, but I got it up to almost 40! It had to have been revving over 10k. My engine is really well balanced, but even still, I do not want to try it again. It's asking for a blown engine. On level ground with no wind, WOT I can hit maybe 32, but I always cruise at around 26 and almost never bring it above 29 because it's nearing redline much past that. If you have the torque, by all means gear it lower.
     
  6. Xiodinc

    Xiodinc New Member

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    How is a reed valve intake better? I'm interested. Also, im going to be putting the 36t sprocket on and see how that goes.
     
  7. Nashville Kat

    Nashville Kat Active Member

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    I seriously don't believe you can get 38 out of a 44 sprocket
    unless you are revving the motor waaay up
    and you'll probably be rebuilding quite a bit
    if that's what you're doing.
     
  8. 2door

    2door Moderator
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    See? This is why I always warn against threads regarding speed claims.

    If you don't agree, move on. No arguments. :(

    Tom
     
  9. crmachineman

    crmachineman New Member

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    Alright! nice exhaust! I can see that bike going that fast! I believe there is a good chance that with a straight crankshaft, proper mixture, and top notch race quality oil, I think you'll be able to get away with that, as long as the piston rings can properly seal at that speed.

    Keep it up!

    .duh.

    -Fred
     
  10. Xiodinc

    Xiodinc New Member

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    I bought this bike used, and every that could be done to improve it, was done. I checked inside the engine, and everything has been balanced, the chain tensioner has been custom welded, along with custom motor mounts and gas tank mounts welded in. This bike is fast. I had it recorded having a car drive right next to me, twice.

    What a deal. I got this thing for 172, all it needed was some new tubes and some more fine tuning.

    I have a go pro and would be happy to film this achievement as well.
     
    #10 Xiodinc, Jul 23, 2012
    Last edited: Jul 23, 2012
  11. young grease monkey

    young grease monkey New Member

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    Reed valve intake is better because the intake is open for part of the piston down stroke with piston porting, and this causes lower case pressure because some of the charge is pushed back out to the carb. At lower rpm, some of the intake air is pushed back and forth in the carb causing it to be too rich. A Reed valve is a one way valve that stops the pulses from exiting the crankcase. They limit high rpm power somewhat, but it wouldn't be noticeable at the rpm China girls should see. It will greatly increase lower rpm torque.
     
  12. Xiodinc

    Xiodinc New Member

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    Do you know anywhere i can buy one?
     
  13. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

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    Where have you been? :) Quite a few of the racing 2 stroke bikes
    are using reed valves and winning! :D

    www.ArrowMotorizedCycles.com makes, races and sells reed valves.

    Rock Solid in OZ makes one too.

    [​IMG]
     
    #13 MotorBicycleRacing, Jul 23, 2012
    Last edited: Jul 24, 2012
  14. Nashville Kat

    Nashville Kat Active Member

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    It's not the speed I'm doubting- it's the practice of running the revs up-

    "using reed valves and winning" is a kind of statement- Yes, I guess there are many here who'll take that approach- I was more speed oriented when I was getting started, even while I was first pretty uncomfortable with the speed my original kit and cruiser got- especially at least until I had the dual brake handle and perpendicular bars.

    The older 50cc carb and standard intake had me bogging down a bit- so I wanted to overcome that.

    But if you want something to LAST- if you want the practicle VALUE of the bikes- if you aren't racing and don't want to be tearing the motor down all the time, I just think 38 on a 44 sprock would be VERY uncomfortable-

    pushing the motor, revving like hades- and revving equals vibration- AND with knobby tread tires here- a further source of vibrations

    If speed is what you're constantly after you may be better off with a motorcycle or dirt bike.

    I still always think of my China Girl in terms of the Chinese Junk boat- here's a little motor for getting around- maybe hauling some things you need- they seem to have developed in china with this Junk Boat kind of philosophy-

    then, what I have done at least, is taken my years of bike racing experience and refined the carriage mostly- a billet intake is the only thing I have special on the motor, and I switched to the 66 Speed carb when it came out. I can PROBABLY do 38- I've been to 35 and don't want to stress the motor beyond that, and I think my analogue bike speedo may read just a tweak slow for 27" wheels- That was on the level even with my 8" rise BMX bars, but that's also with a 34 sprocket. That sprocket gives an almost effortless 25 for the motor, and then 30 starts to feel like it's near some kind of normal "redline" of revs.

    but my bike is more like the family car to me- not really a 200 mph Cobra or anything that I want to max out on-

    I also always wear a cycling helmet and not a DOT helmet- I did get a DOT half helmet for my scooter, but it's weight was aggravating an existing sore neck condition, and the bike helmet is better air vented here in usually hot Florida-

    so 25 or 30 is not like 40 or 50 anyway, and I feel like my light and cool cycling helmet is still very adequate protection. I've quit reaching for speed but like a nice fast and smooth cruise where I can more blend in with traffic speeds on long surface street stretches.

    I like to then hit the kill switch if I Know I'm coming to a stop- and I've said it before- it's just like the moment finishing a fast criterium or road sprint- and that puppy just wants wants to coast and coast forever- sit back and enjoy the QUIET bike ride for a quarter mile or more. Wow, seems like old times.

    Seems like Old Times
    http://www.youtube.com/watch?v=9FAV3zr1PMk
     
    #14 Nashville Kat, Jul 24, 2012
    Last edited: Jul 24, 2012
  15. 2door

    2door Moderator
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    Like I said above: Move on.

    Tom
     
  16. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

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    Actually reed valves give a lot of low end and mid range boost
    without any other performance mods.
     
  17. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    And that's exactly what I did.........moved on to higher ground, at a much higher speed......

    .wee.
     
  18. Xiodinc

    Xiodinc New Member

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    Wow, i dont have 80 bucks to blow on one of those. Ill just slap a 36t on and a smaller jet so im running leaner and at a lower rpm at that speed
     

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