DT 400 Trans problem

Discussion in '2 smokers' started by baybueller, Aug 8, 2017.

  1. baybueller

    baybueller Been here awhile

    Joined:
    Dec 18, 2008
    Oddometer:
    475
    Location:
    Tracy Ca.
    78 yamaha has a tranny problem and needs case split/ surgery. Never done one and would rather not go thru the grief just to find I didn't get it right.
    Anybody know a guy/shop that would know how to work on these?
    Preferably in the Nor Cal area.
    #1
  2. concours

    concours WFO for 48 years

    Joined:
    Dec 2, 2008
    Oddometer:
    7,983
    Location:
    NH USA
    What is problem with it? (Symptom)
    #2
  3. baybueller

    baybueller Been here awhile

    Joined:
    Dec 18, 2008
    Oddometer:
    475
    Location:
    Tracy Ca.
    went from ok to only allowing 2 and 3. checked cam stop, and shifter shaft parts. cycled the drum by hand in the clutch area.
    re assembled and rode thru the gears. Now stuck in 5th.
    Nice old bike but worthless as is.
    Also not picky about local, will ship to someone versed in the old DTs.
    #3
  4. spokester

    spokester Long timer

    Joined:
    Jul 9, 2013
    Oddometer:
    1,837
    Location:
    SE USA
    #4
    baybueller likes this.
  5. concours

    concours WFO for 48 years

    Joined:
    Dec 2, 2008
    Oddometer:
    7,983
    Location:
    NH USA
    The detent spring on my '75 DT400 was mangled, the bullet nose was ok. EASY check from outside....
    #5
  6. baybueller

    baybueller Been here awhile

    Joined:
    Dec 18, 2008
    Oddometer:
    475
    Location:
    Tracy Ca.
    Found a local retired Yamaha mechanic. Split the case and found a rivet head from the clutch hub had jumped over and stuck in the shifter cam.
    Waiting on a couple of parts for reassembly, no damage to gears, forks.

    Attached Files:

    #6
    spokester and JCool like this.