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RM flat spot on landing ???

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by bretto61, Sep 15, 2011.

  1. So while I am injured and cant play I am trying to fix a mates 2stoke RM.
    The things hoots like mad. I love it. Finally got the suspension set for him so he can finish a race and still pull the front brake or clutch in at the end. Or almost lol.
    So now the problem. If you take a double on it and get some good air and come down hard it really bogs down and sort of hits a flat spot for a nanno second. very painful.
    I am thinking they have put a smaller main jet in it. I don't have my jet kit here and cant find any markings on the one that is in it. But a guess from a look tells me it's not the OEM jet. But the thing is running a bit rich ???? Sorry needle setting is on three.
    I am thinking of going down to 5 on the clip and see if that helps. Or am I going the wrong way around
    Any ideas lads ?????

  2. no air leaks?

    when you say it bogs down on landing, i assume this is when you're opening the throttle right up just before you hit the ground?

    whats the plug colour like? what mix of 2 stroke to petrol are you using?

    needle position is for 1/4 to 3/4 throttle.
  3. Is it 'cos the g-forces of the landing cause the float to sink, letting the fuel level in the float bowl rise too high?
  4. Yeah JD the plug is on the black side. Not real rich but sooty. And yup its just a bit of throttle on lading to soften the blow. Not fully open but yeah bout half. Depends on the dangle and length really.
    It just bogs and does not rev up at all. Like you bumped the kill switch for a nanno on landing. I hear it rev up before landing but almost cuts out on impact.
    He is not real confident with air and this is sapping his confidence even more.
    Saying going down I am actually going up in numbers. It's on three and I was thinking going four or five.
    It really seems to come on the pipe pretty hard too. Very doughy under it.
    Just writing this thinking. I am going to check his wiring to the kill switch and make sure it's not earthing out on something. Never know.
  5. 5 is top most on the needle? That will make it leaner, if so.

    Could also be electrical, as you say, although my motorbikes usually stay on the ground, so I'm not really versed in this type of thing...

    There was this one time, with some tram tracks late at night, but nothing like you're describing.

    I'd do some electrickery checking.
  6. Lift the needle to open up the jet for more fuel, so moving the clip to the bottom groove of the needle. I always counted from the top not the bottom.
  7. I reckon PatB's on the money. Check your float height. And the float itself for signs of damage or sinkage. If the jetting were way up the shit, it would run crap all the time. Not just landing jumps.
  8. Electrics look good. All sealed and no frays. No contact marks.
    Sorry it has a pipe on it too. I don't think the jetting was done with any care.
    Thinking I will take it all back to stock and work form there.
    Thanks heaps for the help guys. And yup Pat I think your dead on it. When are you opening a shop lol