XL 250 build

Discussion in 'Old's Cool' started by pommie john, Sep 4, 2011.

  1. Al Tuna

    Al Tuna doldrums

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    That pipe looks damn good! Hope it fits.
    #21
  2. brucifer

    brucifer Long timer

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    Yeah, that pipe does look good. Nice job. :thumb
    #22
  3. pommie john

    pommie john Long timer

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    It fits!

    [​IMG]


    The curve worked out about right. It tucks in just how I hoped.
    [​IMG]


    I've also been given this muffler. I'm thinking about trying to make it fit a bit like this

    [​IMG]
    #23
  4. Pigford

    Pigford British

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    That pipe is well smart :clap How about just fitting a small baffle & turning up an nice ally end-cap to tidy it up - less is more :wink:
    #24
  5. pommie john

    pommie john Long timer

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    Yeah, good idea. The only worry is that it has to comply with racing rules which are 103 dB measured at half a metre from the exhaust at a prescribed RPM. That sound a lot, but when the noise meter is so close, it's quite an ask from a small baffle. I definitely agree that less is more, it's how much less I can get away with.
    #25
  6. pommie john

    pommie john Long timer

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    It's pretty well finished.

    A few details to be tidied up. The problem is, that although it starts first kick ( without the choke) it runs really rich and won't accept full throttle without spluttering. Also it idles best with the pilot screw fully in. Gotta be something wrong in the carb.

    I'm thinking blocked air passage somewhere.

    [​IMG]

    [​IMG]
    #26
  7. bikerfish

    bikerfish flyfishandride

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    those needles and seats were known to wear out, leading to all kinds of carb issues. I've replaced a few of them and they ran like new afterwards.
    that thing looks REALLY nice!
    #27
  8. pommie john

    pommie john Long timer

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    Thanks, I'll have a look at that.
    #28
  9. raytriplej

    raytriplej Adventurer

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    Nice work on the XL. Thinking outside the box!

    Ray
    #29
  10. pommie john

    pommie john Long timer

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    Thanks.
    I think it's finished now. I have a race next weekend . I put a dellOrto carb on it and set the points up properly and it seems to run pretty well now. My neighbours didn't like it too much, but....
    #30
  11. pommie john

    pommie john Long timer

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    First race meeting, and it went well, after some hassles.

    It was a very small, low key race but great fun.

    In practice it wouldn't work on an even throttle. Mid corner it was popping and banging and dying. I raised the needle and went out in the first race hoping I'd fixed it. Well, it was a little better but not much, then after a few laps it died completely.

    This ended up being a good thing because I then had a total failure to trace instead of a difficult running problem, and as we all know it's easier to find a terminal problem than an intermittent one.

    The advance retard mechanism had completely fallen off!

    When I put it back on it ran like new. clean crisp and tons of mid range power. It had obviously been loose all along and giving me variable timing.

    I was racing with some K4 Hondas and a couple of two stroke Suzuki twins. Once I got used to the bike I managed to beat the Hondas in every race and all but one of the Suzukis, so I'm really pleased with the way it went. It handles very well, despite everyone telling me the front tyre's too big. I may have to move the footrests soon as they started to hit the ground when I got into the swing of it.

    I got infront of the Honda
    [​IMG]

    Never caught that Suzuki
    [​IMG]
    #31
  12. brucifer

    brucifer Long timer

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    Nice! Good job, man! :thumb
    #32
  13. anonny

    anonny What could go wrong?

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    Beauty, nice work John :clap:clap
    #33
  14. rpet

    rpet Awesometown

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    Nice build man
    #34
  15. pommie john

    pommie john Long timer

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    Took the XL for a race at Townsville. It's a kart track really, but quite well suited to a little bike like the XL.
    Notice the puff of smoke. There's a score in the cylinder that I hoped wouldn't matter, but I guess it needs a rebore. and new piston.

    <iframe width="420" height="315" src="http://www.youtube.com/embed/zufll9R0aYI" frameborder="0" allowfullscreen></iframe>
    #35
  16. cam14

    cam14 Been here awhile

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    Looks like a lot of fun and you've done a great job re-purposing that XL250. If you do a leak down test and results are acceptable, then would not be too concerned with a little smoke.
    #36
  17. BIG ED XT FAN

    BIG ED XT FAN Long timer

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    I have about 5 of them XL250, and never think of roadracing it. Great job!! Thanks for posting the movie.:lol3
    #37