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78 Yamaha xs400 2A2 Piston/Rings Engine overhaul

Discussion in 'The Garage' started by Viking, Dec 11, 2019.

  1. Viking

    Viking XS400 New Member

    I have taken my pistons out and tried refitting new rings (+0,0) and when i push the rings in the cylinder to check the ring clerance/gap and the gap is about 0.8mm and the book says it´s max 0,02-0,04mm
    I have measured the cylinder and pistons and they are in spec !
    So the question is ! Have i missed something,or have i got the measurments wrong ?
    Any hlp would be apprecited :)
    Thanks in advance :)
  2. Which tool did you use to measure the cylinders?

    I thought mine were in spec years back till I bought the proper tool.
  3. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    The Haynes manual spec for end gap is .2 - .4mm for the top and 2nd ring and .2 - .9mm for the oil ring
  4. Gra900

    Gra900 XS400 Addict

    Hey Viking, 0.02 to 0.04 mm is very small, about the same as a hair so new haven mikes figs make much more sense
    Post some pics of the rings in the bore if you don’t have the tool
  5. Viking

    Viking XS400 New Member

    Jesus christ :( I have looked at the wrong at the wrong numbers ! Have been sitting still now for a month, and bought oversize rings !
    Well this changes everything :) thank you guys for correcting me :)
    Cant get over that i missed this :)
    Cheers everyone :) Ride safe

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