Honda XR80R Service Manual

Remove any carbon deposits f rom the piston ring
grooves. using an old piston ri ng as shown.
Tem poraril y inst all the pist on rings to their pro p er
pos i tion with the mar k facing up .
Measure the pi ston dng- t o-'ing groove clea ra<'\Ce
w il h the ri ngs pushed inlO the groo ves.
SERVICE LIMITS:
Top: 0.10 rnm (0.004 i nl
Second: 0.10 rnm (0.004 i n)
I nspect the piston f or wear or dama g e.
Measule t he diamete r ot the piston at spec', I"Ca ( IOn
given 110m the bonom and 90 degrees to the piston
pin hole.
PISTON 0 .0 . MEA.SUREMENT POINT
XR100R: 10
mm (0. 4 ifl)
XR80R: 7 mm (0 .3 in)
SERVICE LIMIT:
XR100R:
52.90 mm (2. 083 I nl
XR80R: 47.40 mm 11.8 66 in)
Measure the pisl on pin bore.
SERVI CE LIMIT:
XR100R: H .04
mm (0.553 in)
XR80R: 13.04 mm 10.5 13 in)
Measu re the O.D. of the pisto n pin .
SE RVICE LIMIT :
XR100R:
13 .96 mm (0.550 i nl
XR80R: 12 .96 mm (0 . 51 0 in l
Ca l cu late the piston-Io-piston pin clearance
SERVI CE LIMIT: 0.020 mm ( 0_0008 in)
kRl0 0R:
,Omm <0 .' " ',._ ,
XR80R :
7 m m (0.3 inl
CYLINDER/PISTON
8-5

Honda XR80R Specifications

General

Displacement	79cc
Compression Ratio	9.7:1
Fuel System	Carburetor
Ignition	CDI
Transmission	5-speed
Final Drive	Chain
Front Brake	Drum
Rear Brake	Drum
Front Tire	2.50-16
Rear Tire	3.00-14
Ground Clearance	9.1 inches
Engine Type	Air-cooled single-cylinder four-stroke
Bore x Stroke	47.5mm x 45mm
Rear Suspension	Single shock