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TTR250 air balancing

Discussion in 'Bling and Appearance' at netrider.net.au started by jeffatav, Apr 7, 2007.

  1. I have just given my recently purchased TTR250 a service that included a K and N filter to replace the foam filter.
    The bike has a staintune muffler and it sounds like there are no baffles in it.
    The air box has about five 25mm holes drilled into it to increase air flow, but I don't know what other mods are in it.

    I also changed the plug and a NGK cr8e came out and the recommended NGKcr9e was installed along with a new battery. Any difference in plugs????

    The trouble is I can't seem to get the air/fuel mix right and it doesn't idle well.

    I have now put back the original filter in an effort to regain the balance.

    Any other "tricks" I should know about???


  2. Did it idle before?

    The system sounds like its pretty free flowing so a fiddle with jets and needle could be in order. Does it make power or just more noise the harder you twist the throttle?
  3. at the moment it will start with full choke and rev its tits off and then die when I put the choke in.
    can't get it to idle!
    time for a beer!!!!!
  4. The K&N filter and staintune will make a huge change to it's breathing so your mixtures will be well out. As an ex mechanic I can't say I like K&N at all...... but if you're planning on offloading it before all the stuff that k&N's let through into your engine (dirt, dust, passing pedestrians) then I guess thats someone elses issue....

    Generally a motorbike carby needle has about 5 "positions" that can be used for adjustment, other than that you will need new carby jets.

    I cant say im a fan of "drilling holes in the airbox" to increase flow. Those things are designed with a lot of R&D and often the results are way worse when people do this, not better. I dont think that pronciple has worked properly since the early 80's :p

    Plastic trumpets put on a factory airbox to meet noise restrictions for a specific market though is a different matter.

    One range of plug shouldnt make too much difference.

    Any improvement just running the normal air filter?
  5. see post above!!!

    I reverted back to how I found it with the foam air filter etc.
    I even checked the valve clearences, spark plug clearance, etc etc.

    It will start from cold with full choke and revs its tits off, but when I try to put choke in, she dies and doesn't want to start again.

    I am thinking almsot flooded type symptoms.

    Might have to see the pros!!
  6. try some gaffa tape over the holes?