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Heiden Dyno Tune Needle & Jet Kit

Discussion in 'The Garage' started by Lunatic, Apr 22, 2010.

  1. Lunatic

    Lunatic XS650 Enthusiast

    Hey all, quick question about the Heiden Dyno Tune Needle & Jet Kit from Mikes/xs650direct.

    In the kit there is a drill bit and instructions to drill out the slide vacuum port. What is the purpose of this?

  2. Freak

    Freak XS650 Enthusiast

    I used this kit in my rebuilt carbs and just to say it worked great, I run open headers with mikesxs pod filters. The answer to your qeustion is I believe to allow more air flow, Well lets say more air flow quicker.
  3. XSLeo

    XSLeo XS650 Guru Top Contributor

    Drilling out the hole in the slide makes the slide lift quicker. Enlarging it to much makes the slide flutter. The slide lifts to fast, Runs out of vaccum, drops to quick, regains vaccum rises to fast, loses vaccum, drops to fast. Thus the flutter. This is not a good thing.
  4. Does anybody know the measurment for that drill bit? I found some little washers in my garage to shim up my stock needs to richen them up, but need to drill the slide hole bigger. Is that what would cause the stuttering (hesitation) when you twist the throttle under a little bit of a load?
  5. What size pilots come in that kit? Do you have a way to take a pic of the intruction. I have eveything in the kit, just not the instuctions or a drill bit size fo refrence.
  6. Lunatic

    Lunatic XS650 Enthusiast

    After going through hell with my carbs, I wouldn't drill out the hole. It's working ok for me now, but not with the heiden needles. I'm using the stock (Canadian) needles and stock jetting, even with pods and straight pipes.

    I would leave it all alone and start from stock and proceed with tuning from there.

    If you are hesitating at part throttle it's probably pilot jet or needle position.

    Go back to 100% stock and then make one change at a time and see what happens.
  7. Gordon

    Gordon XS650 Junkie

    I had that kit on mine. It was ok, but not what I expected. Got a set of XS John's needles, and they are excactly what the old girl was crying for. Worth every penny, IMHO.:thumbsup::thumbsup::thumbsup:
  8. I'm getting kinda sick of these BS carbs. Whould I just be better of getting a new set of VM36s? I can get these right. Stock pilot is to lean, one size up makes the bottom of the midrange too rich. I've f'ed with screw to no help. It is either sluggis from start or stuttering and black plugs at 1/4 throttle. I really hate how easy these carbs rev on there own and have they do have a good snap to them because of the retarded idea of vaccum controled slides. I never had these problems with reg. carbs. The XS750 I had was complete pain in the ass too.
  9. get a set of cdn needle jets and needles, set to stock jetting, maybe one up on the main.
  10. Mike's is out of the needles and has been for months. My main is awsome from 1/2 to full.
  11. Whould changing the air jets change anything in the low range. Would bigger air jets make the mix richer or leaner. I'm thinking leaner right?
  12. yep, but i think it changes it across the entire range.

    Re: jet availability: just checked. They're in stock. Maybe just not in the states?
  13. I was wondering, I had straight pipes on it befor and the jetting was fine. I was using the stock headers so the inside was really small. Now I got a set of 1 1/2" straight pipes all the way so they are bigger. Could it be making the midrange too rich? It sounds wierd, but I added two groves worth of washers under the needle to raise it, but it makes it worse the higher it is. It stutters bad from about 1/4 to 1/2 throttle then clears out and runs awesome all the reast of the way. Also if you rev it past 1/4 throttle at an idle it won't come back down without a load. The advance spring are perfect opening at about 2000 rpm and the Pamco is dialed in perfect. Considering it gets worse from jetting it looks to be the problem.
  14. go up a size on your pilot. That should calm it down.
  15. I got it to quit by putting a smaller air jet. I think the stuttering is from this 30t sprocket. I like the rpms but I don't think the stock motor has the balls to pull it at the bottom of the gears. It quits the stuttering from 4th to 5th. And it doesn't do it at all when you run the gears high.
    Last edited: Jun 19, 2010
  16. Muneio

    Muneio XS650 Argonaut

    Where do you get the Canadian needle jets and needles?
  17. Muneio

    Muneio XS650 Argonaut

    Thanks INXS so to clarify for an 81 XS650 I would order the following:

    Jet Needle 5IX11 Part #48-0663

    and Needle Jet 336-Y0 Part #48-0662
    is that correct?

    Thanks Bill
  18. Muneio

    Muneio XS650 Argonaut

    Thanks again!

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