1997 DR350SE runs lean @ cruise.

Discussion in 'The Garage' started by doggitter, Feb 15, 2014.

  1. doggitter

    doggitter Long timer

    Joined:
    Jan 4, 2014
    Oddometer:
    2,125
    Location:
    Elmira, Oar-agin
    Full throttle no percieved problems, idles great, real low speed light throttle is good. But, I get to 45 and on up on steady cruise and it's hunting/surging continuously. My guess is either the needle needs set higher, or needs a needle with faster taper. I don't know bike carbs much at all, let alone the CV that I think is on here? Do they even have a tapered needle like the bikes I had 20-30 years ago?
    If so am I in the ball park with moving the needle up? How do these vacuum sucker carbs funtion as far as cruise mixture goes?
    #1
  2. Chiknmunky

    Chiknmunky Adventurer

    Joined:
    Sep 16, 2010
    Oddometer:
    89
    Location:
    On road Off road
    I have a 99 DR350 that started doing this after I cut the top of the airbox to work with the adj needle and bigger main jet I got from Kientech. I put a preload spacer (4 mm) on the spring that is on top of the slide. I have not had the problem since.
    #2
  3. doggitter

    doggitter Long timer

    Joined:
    Jan 4, 2014
    Oddometer:
    2,125
    Location:
    Elmira, Oar-agin
    I was reading your telling of that but don't know if this is the same situation(carb) to go that route.
    Any "gotcha's" in trying to do this for my first time on this bike? Pull the carb off the bike first or pull the tank or which route?
    #3
  4. Chiknmunky

    Chiknmunky Adventurer

    Joined:
    Sep 16, 2010
    Oddometer:
    89
    Location:
    On road Off road
    If you have the CV carb, take the black plastic top off. Under that top is the bladder and under that is the spring I'm talking about.If I remember corectly I put the spacer between the spring and the bladder.I'm not sure if you can get to it without removing the carb or not. (probably not)
    My bike was doing exactly as you described,idled fine and as long as you were on the throttle it was good but just cruising along it would surge pretty bad.
    All I could figure was some how at cruising speed the neddle was moving up and down, so I thought if I could put a little more tension on the spring it may help.6 0r 7000 miles since I did this and I have not had the problem.
    #4
  5. AustinJake

    AustinJake TE450-KLE-FXDWG

    Joined:
    Aug 20, 2010
    Oddometer:
    3,913
    Location:
    Austin, TX
    Do you have a DJ needle in the bike?

    I had this problem with a street bike that had a DynoJet needle in it, the ones with the tapers, at cruising speed, the tapered part was right at the jet opening and causing the surging/hunting. I replace the DJ needles with stock needles, problem solved.

    [​IMG]
    #5