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'92 XR80 - what to do?

Discussion in 'Mini Racing' started by pjzocc, Apr 13, 2013.

  1. pjzocc

    pjzocc Well-Known Member

    I've got an XR80 that I've been using as pitbike/yard bike to eff around on. It's lost compression (~70) and I'm looking at a couple hundred to order a new piston kit, gaskets, rebuild, etc... Don't really wanna spend it on the bike. IF I could find a working 100 motor (and it'd fit) for a couple hundred, I'd consider that route. Anyone know if this swap would work?

    Otherwise, if anyone has any interest in the bike, I could bring it to Summit next weekend. PM me.
     
  2. pscook

    pscook Well-Known Member

    The 100 motor should drop right in as well as use the same exhaust. I can't speak to the electronics or carb, but they should be compatible. The difference between the 100's and 80's is the swingarm, everything else should be compatible.
     
  3. pjzocc

    pjzocc Well-Known Member

    Thanks. I'm looking but not too many complete motors out there. Really don't wanna shitcan the thing... it's really been a fun little neighborhood terrorizer!
     
  4. Kurlon

    Kurlon Well-Known Member

    80 has a better transmission ratio package. :D
     
  5. backcountryme

    backcountryme Word to your mother.

    The xr80 gears will fit in the xr100 bottom end too.
     
  6. pscook

    pscook Well-Known Member

  7. pjzocc

    pjzocc Well-Known Member

    Can anyone confirm the stock bore size of this bike? I'm searching but I'm getting conflicting #s. I THINK it's 47.5mm, but I've seen 45.5mm, 46mm... :confused:

    If it's 47.5, can I shoehorn in a 48mm piston without boring out the cylinder? Seems 47.5 is an odd size...

    (*disclaimer: I'm not much of a mechanic so I apologize for the dumbdumb questions!)
     
  8. backcountryme

    backcountryme Word to your mother.

    47.5mm bore 45mm stroke. You would still need to bore it to fit a 48mm piston.

    Also the xr80 has a 13mm pin. The xr100 has a 14 mm pin.
     
  9. pjzocc

    pjzocc Well-Known Member

    Thanks!
     
  10. YZROOSTINYA

    YZROOSTINYA Well-Known Member

    the 100 has a 24 mm carb as well. the intake body on the head different as well. the xr 80 carb has bolts that come from the carb, the 100 has bolts that come from the intake. the xr 100 head is different as well. stock 100 is 9.1:1 and 80 is 9.5:1
     

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