2 stroke experts!

Discussion in '2 smokers' started by craftsmanracer, Apr 8, 2012.

  1. craftsmanracer

    craftsmanracer Been here awhile

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    I am completely stumped as to why my old enduro is misbehaving...

    It is a 1977 Kawi KE-175 rotary valve, and it has starting issues.

    It will sit for a month at a time, and start on one kick, but if I let it sit for less than a day, it will take AT LEAST 50 kicks to start it. It is like it doesnt like being used on a regular basis.

    The carb is clean, the plugs are fine, and the gas is fresh. I just removed carbon from the head and gave it a new head gasket, as well as cleaned out the exhaust. The bike also didnt come with a choke, and I removed the oil tank and run a 32:1 premix.

    I make sure to shut the gas off when it isnt running.



    oh, and it has always done this, even before I did the work to it.
    #1
  2. willis 2000

    willis 2000 neo-quixote

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    A poorly-sealed bottom end will cause this and other odd symptoms. Remove the carburetor and crank the engine slowly until the cylinder transfer ports are closed by the piston, but the rotary valve is somewhat open. Stick your face into the area previously occupied by the carburetor and blow into the carburetor mounting stub. Listen to where the air is escaping. Coming out the exhaust? Move the piston, your transfer ports are open. It will probably show the LH crank seal needs replaced. Face too big for the carb area? Get a kid, make 'em earn their keep. DAMHIK
    #2
  3. dooder

    dooder Adventurer

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    Did you try Willis' advice Craftsmanracer?
    Any update?
    #3
  4. craftsmanracer

    craftsmanracer Been here awhile

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    Yes! i had a cracked carburetor boot, and extra air was leaking into the engine, causing the air/fuel mix to get all screwed up.

    I also think it would start after sitting because it gave the carb time to leak gas into the motor wich "choked" it.


    Unfortunately though, 2 days ago, I was doing a very aggressive sprint down a dirt road, and the bike lost power, and wouldn't start up again.


    Took it home, and blamo!

    [​IMG]

    So now I got to get a new piston, and probably split the cases to get the pieces of smoked piston out of the crankcase.

    Unless anyone else has an idea????
    #4
  5. AC Swank

    AC Swank Banned

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    Running a bit lean there.

    Turn the motor over and flush out the bits with kerosene, there is no need to split the cases. All that is going to wash out is pepper sized bits, anything bigger was already blown out the exhaust.
    #5
  6. craftsmanracer

    craftsmanracer Been here awhile

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    Thanks for the advice! I was scared that I would have to deal with full blown surgery, and disassembling the rotary valve system, wich I am sure needs special tools to do.

    So I just take the cylinder off, pour some kerosene in the motor, and turn it back upside-down?
    #6
  7. LasseNC

    LasseNC XSessive!

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    I'd suggest figuring out why it was running lean, otherwise you'll just end up the same way again.
    #7
  8. AC Swank

    AC Swank Banned

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    That's it.

    Back in the day, it was normal to remove the head after each race to check the condition of the top of the piston and change it before he hole got too big. Many of us who also rode 2 strokes on the street did the same every other month.
    #8
  9. Shocktower

    Shocktower Long timer

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    If I recall the rotory motors need the injector system to lube it correctly, you may have more problems, than you think, I would stick with the stock set up JMHO
    #9
  10. AC Swank

    AC Swank Banned

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    Shocktower is correct, rotary systems require the oil injection or say good-by to the bottom end bearings. :thumb
    #10
  11. craftsmanracer

    craftsmanracer Been here awhile

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    Nope, that is if the bike had injecto-lube, that only came on the bigger bikes, mine has super-lube, wich can be bypassed.

    Got a new piston in the mail, I will put it in soon.


    I am wondering about the seal behind the magneto being blown out too though, so I was thinking about sealing up the magneto cover so that extra air can't get in there.

    I plan on taking marine 5200 sealer and going to town on the thing.


    It is a $300 beater bike, so I just need it to run, not be pretty.
    #11
  12. willis 2000

    willis 2000 neo-quixote

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    Don't even try it, the seal is leaking and you'll blow another piston if the seal is not replaced.
    #12
  13. AC Swank

    AC Swank Banned

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    I was kinda hoping he was going to do as he says, he'll be back for more advice.
    #13
  14. Shocktower

    Shocktower Long timer

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    Fixt :lol3
    #14
  15. AC Swank

    AC Swank Banned

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    Yes, a blown piston does make a good ash tray. :eek1
    #15
  16. JRP

    JRP Old guy

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    What plug are you using? The stock B7ES is fine in most cases but you might want to go to a B8ES, since you have already ventilated one piston. :D
    #16
  17. MORT666

    MORT666 Been here awhile

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    Has it got ignition points this can alter the ignition timing:norton.
    #17
  18. craftsmanracer

    craftsmanracer Been here awhile

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    I'm using the reccomended b7hs, and it is a cdi bike, so no points.

    I know I am gonna sound like a cheap-o halfass lazy mechanic, but I really think I can seal that cover up, along with the wires coming out of it, and if I make the bike run hella rich, I dont think it would have any problems. I'm fine changing out plugs when they foul, and I have a strong kickstarting leg.

    :D
    #18
  19. JeffS77

    JeffS77 cheap bastard

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    running with a bad flywheel side seal you are just asking for trouble even if you try to seal the cover...how much is the puller ?? like $12 and the seal $6 ? seems like cheap insurance to insure you don't have to do a complete top end rebuild
    #19