How to know when broken in? Fuel ratios?

Discussion in 'Motorized Bicycle General Discussion' started by michaelbikin, Jul 30, 2015.

  1. bairdco

    bairdco a guy who makes cool bikes

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    Besides race bikes I've built, ran lean, hoping they'll go 30 laps or so, I've never siezed a street bike from the wrong mixture.

    It's always been a mechanical failure (or a better description would be cheap chinese manufacture failures.) Blown main bearings, losing the ring keeper on the piston, rods stretching just enough to slam it into the spark plug, or other parts disintegrating, not from lack of oil or over heating.

    Race bikes, different story. Bumping up the hp to it's threshold and beyond, running max rpms non stop, over revving and slipping the clutch til it screams, that kills 'em.

    Started running racing oils with castor sauce in them at around 16:1, and they stopped overheating. Still blew up when the aforementioned cheap internals failed, but not from lack of oil.

    Plus it made a good, stinky, smokescreen for the poor guys behind me.
     
  2. 2door

    2door Moderator
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    This is what I love about this forum and this hobby. Nobody is right and nobody is wrong. You do what you do and it either works or it doesn't. If it works, you did it right. If it fails, you still probably did it right, but got something else wrong :)

    Nothing is carved in stone. Except, using those stupid plastic spark plug boots that come in the kits and packing a crankcase with JB Weld. :)

    Tom
     
  3. Davezilla

    Davezilla New Member

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    Now if you want to stink out the guys behind you just add a small amount gear oil or Rotella to your mix...
     
  4. Davezilla

    Davezilla New Member

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    ... And all this time I thought you had to put jb weld in your transfer tunnels if ya wanted to go fast... laff
     
  5. michaelbikin

    michaelbikin Member

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    Very funny, I am not racing at the moment, I'm more of a street rider, but that sounds like a good thing to stink up the exhaust
     
  6. bairdco

    bairdco a guy who makes cool bikes

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    Add a coupla drops of atf straight into your carb and it'll blow a smoke screen out so big no one would be able to pass you.
     
  7. Davezilla

    Davezilla New Member

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    Yeah, ATF is nasty too...
     
  8. 2door

    2door Moderator
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    We used to use ATF to make smoke from R/C planes. Actually we also mixed it with a little kerosene or diesel. It was injected into the muffler from an exhaust pressurized tank and a servo operated mini-valve. Pretty against a clear blue sky.

    Tom
     
  9. xseler

    xseler Well-Known Member

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    I used to de-carbon old carburetor equipped cars with a shot of brake fluid poured down the throat of the carb while the car was running. Made one **** of a sweet smelling smoke screen. Had to make sure the car didn't have a catalytic converter as you could hear the carbon 'tinkling' down the exhaust pipe.

    Probably illegal, but it sure cured driveability problems!
     
  10. 2door

    2door Moderator
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    LOL,
    ATF, brake fluid, all those things the EPA would have a heart attack with if they caught us doing today. Homeland Security would have called in the 'S-W-A-T teams if they had seen us dumping ATF into brand new Chevrolets to clean out 'gunked up' carburetors before they were delivered to the new owners back in the 60s.

    Tom
     
  11. Davezilla

    Davezilla New Member

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    I also save a few gallons of used ATF at the shop since it's such an excellent cleaner, just soak your carbon or crud coated parts in the ATF over night and it'll be nice and clean the next day... Running ATF thru the carb on an old RX7 will also breathe new life into the engine by de carbonizing the apex seals...
     
  12. LandSpeedRecord

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    Good trick for the RX7. I had a 2nd gen RX7 that I could get the metering pump to stick on and the smoke screen looked like the world was ending behind me ha ha. As for these little 2 strokes Baird nailed it, they just need oil. I think they are so inefficient at combustion And transfer that virtually any oil type substance will drop out of the gas and keep everything lubes. Balance and a whole bunch of other factors are the death of probably 99% of these and not lubrication.
     
  13. michaelbikin

    michaelbikin Member

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    What do you mean by balance?
     
  14. Davezilla

    Davezilla New Member

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    Most these engines are poorly balanced and will shake themselves... and the rider to death... I usually buy bottom ends with balanced cranks and upgraded bearings which helps a lot. Thatsdax.com sells really nice balanced bottom ends and engines and I've ran these at 10,000+ rpm with no serious vibration issues... some of the ebay specials I've used tho are a totally different story and shook like crazy at just moderate rpms.
     
  15. Whiteride

    Whiteride New Member

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    Sad thing is no matter how carefully you baby it. It will fail at the worst time, and for no apparent rhyme or reason. With their poor construction and outdated design these little engines require an inordinate amount of care and tinkering and despite one's best efforts, are doomed to fail. My No. 1 rule? Never ride any further than you're prepared to pedal back.
     
  16. 2door

    2door Moderator
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    I'm sorry that you have had such bad luck and trouble with your bike however there are many of us who have accrued thousands of miles from a Chinese 2 stroke engine.
    Maybe it's time you examine how the engine is installed, maintained and ridden before making a blanket observation based solely on your single experience.

    I ride my bikes daily and I trust them to get me to where I want to go and home again and never consider that they'll leave me stranded, or walking. They haven't yet.

    Just my experience, but one shared by a good many builders here.

    Tom
     
  17. xseler

    xseler Well-Known Member

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    No walk'n for me in the past 2 1/2 years. Been more reliable than most folks I know.
     
  18. Mike B

    Mike B New Member

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    You lie like a dog. One of your "magnificent machines" vibrated it's fender off and put you in the hospital. Your mommy had to come and get you and the wreckage off the road.

    I guess you are right, the motor didn't conk, but it caused you to conk eh?
     
  19. 2door

    2door Moderator
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    It wasn't the bike's fault. That was a failure of something I overlooked , and the bike in question wasn't built in China. Get your facts straight before calling me a liar. Also the discussion was about the engines, not the bike itself.
     
  20. bairdco

    bairdco a guy who makes cool bikes

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    Damn mike, that was a pretty harsh. Totally uncalled for. Every experienced builder I know has taken a spill, including me. And i can't think of one time it was due to engine failure.

    I blew an engine at 62mph, and rode out of it unscathed, mostly because at that speed it blew apart instead of seizing up, 'cause the rest of the engine just disintegrated.

    And I flipped over the bars at 45 because of a tiny little bolt failure on my front brake, landing me in the hospital and altering my life forever.

    Yeah, these motors can suck, blow up unexpectedly, frustrate the **** outta you, but you don't have to be a jerk about it.
     

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