Honda CB160 piston clearance; Factory manual typo?

Discussion in 'Old's Cool' started by TheRadBaron, May 14, 2013.

  1. TheRadBaron

    TheRadBaron Been here awhile

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    Does anyone have the proper spec for piston-bore clearance for a '66 Honda CB160 twin?
    The factory Honda manual that I have states that the clearance should be .004-.008", but that has to be a typo because that's WAAAY too big. For example, the manual for my Honda XL125 gives the clearance for that engine as .0004-.0020". The CB160 should theoretically be even smaller than that since the bores are smaller.
    Anyone know the proper spec? Thanks.
    #1
  2. caponerd

    caponerd Kickstart Enthusiast

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    I have a CB160 manual, but I'm at work, so I can't confirm it, but my recollection is that I had the impression that the clearance number seemed strange to me when I looked at it.
    I have no idea if that's a typo or not, but if two different manuals have the same number, (assuming they're not from the same printing!), maybe it really is what they should be set to.
    #2
  3. robtg

    robtg Been here awhile

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    That has to be a typo. I worked for a Honda dealer back in the '60s and raced a 160 bored to 175. We gave the piston .002" for extra clearance.
    .0015" clearance was the middle of range if i remember.
    #3
  4. TheRadBaron

    TheRadBaron Been here awhile

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    That sounds precisely like what my machinist and I have agreed it should be. I'd just really like to find something officially in print before I tell the machinist to pull the trigger on the final honing.
    I'm rebuilding this motor for a buddy and it's the first time I've ever done major work on an old bike for someone else. My reputation as the local Jap-bike guru will be damaged if I give the guy a motor back with funky piston issues.
    #4