Kawasaki 1986-1987 Rear Suspension
The 1986 and 1987 versions of the Kawasaki KX80 are virtually identical except for in five areas: (1) The frames have a different lower chain rollers, (2) The rear suspension has different geometry and was beefed up for 1987 (3) a vented front brake disc was introduced in 1987, (4) the rear brake torque arm was slotted in 1987 and (5) the airbox was altered in 1987 to accommodate a larger air intake duct.
Add to this list that for 1987, Kawasaki introduced its first Big Wheel 80cc model meaning three separate suspension layouts. The upper and lower lever arm bolts were increased in size from 16mm to 18mm for the 1987 season. 1986 models suffered many failures due to sheared lever arm bolts (to which this author can attest!), so the changes for 1987 were welcomed.
The swingarm and lever arm and linkage combination for the 1987 Big Wheel and Small Wheel models is interchangeable as the frames are identical in every way. This means that the 1987 Small Wheel models can be upgraded to a Big Wheel version. The catch? You need to buy the correct swingarm and linkages. You can get it here: OEM Kawasaki KX80J 1987 Suspension Arm and Linkages Set (3 PCS) – OEM Motorcycle.
We also offer a full big wheel conversion kit: OEM Kawasaki KX80 1986-1987 Big Wheel Conversion Kit – OEM Motorcycle.
What about the '86 model. Can I convert that to a big wheel version? No. Whilst the 1986 and 1987 frames have similar geometry, the rear suspension does not. Different cushion lever, linkages and bolt sizes mean a different frame connection point for the cushion lever. The brackets are entirely different. Additionally, the top mount bracket for the shock absorber is also different.