1986 & 1987 Kawasaki KX80s

All new for 1986, the Kawasaki KX80 (G1) hit the track with a new look, changed engine and new bottom-link Uni-Trak updated suspension package.

The new plastic work provides the most obvious visual clues of the changes made from the previous model which was largely unchanged aesthetically from 1983-1985. The bike's profile was changed with a slightly smaller, differently shaped fuel tank, a narrower radiator was covered by a new shroud that fastens to the tank better for a stronger radiator mount. This made the radiator less obtrusive and provided a better plane for the rider's knee to slide along. New side panels, a seat with a flatter profile and the rear fender attach to a removeable rear subframe made from round steel tubing.

The big story of the rear section however is the new, bottom-link Uni-Trak suspension layout. The steel, square-tube frame carried only the upper shock mount rather than the mid-frame rocker arm formerly used by Kawasaki. Now, all the moving parts were at swingarm level or below. Less weight, less complexity and a lower centre of gravity.

Kawasaki didn't count on the linkage alone for a better rear suspension - there is a new, rebuildable KYB remote reservoir shock - a far more sophisticated shock than any Japanese mini had featured before it. The new shock had a preload adjustment and adjustable compression damping (just like the big bikes), where the previous year's model had a five position preload and adjustable rebound damping only. There are four compression settings and four rebound damping settings on the shock. Additionally, the stoke of the shock is longer, resulting in 11 inches of rear-wheel travel.

The new frame, larger than that of previous KX80s allows more room for taller riders.

A new fork featured longer travel to match the rear (11 inches) and larger inner fork tubes. The stanchions are now 35mm in diameter compared to the 33mm units of 1985. Tapered roller bearings were adopted for the steering head replacing the older-style ball bearing design. The front axle was enlarged however the front disc brake system was largely unchanged from 1985.

The rear wheel was given the same straight-pull spokes that were introduced on the front in 1985.

Major changes were the order of the day in the engine bay - the whole top-end was turned 10 degrees on the cases to provide an exact alignment of the intake and exhaust ports. Kawasaki didn't simply relocated last year's cylinder: The intake port size, shape and layout are different to the 1985 model, as are the sahpe of the transfer ports and the exhaust port. A larger for-petal reed valve was used in place of the former two-petal design.

The transmission was lightened by the use of a lighter shift drum, where two grooves handle the same shifting chores that three grooves used to do. An indirect-drive coolant pump replaced the direct one used previously. It featured a smaller impeller with a different shape to reduce coolant pressure and prevent coolant from leaking past the pump shaft's oil seal at high rpm. There was also a different primary drive ratio: 3.4:1 in place of 3.083:1 in 1985. The smaller 68/20 gear combination proving lighter than the 74/24 gears previously used.

The 1986 (G1) and 1987 (G2) versions of the Kawasaki KX80 were virtually identical except in seven key 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 stay was slotted in 1987 and (5) the airbox was altered in 1987 to accommodate a larger air intake duct (6) Minor jetting changes in the carburettor and (7) subtle changes to the bike's graphics were also introduced in 1987.

1987 also heralded the introduction of Kawasaki's first big-wheel model (J or J1). Aimed at trying to keep larger riders longer in the mini-class and dubbed a "super-mini" in the United States, the big wheel model was released in different guises around the world in both 80cc and modified 100cc versions. All models featured a revised rear suspension layout including a longer swingarm and rear brake stay, slightly stiffer front fork and rear shock springs and larger wheels (19 inch front and 16 inch rear in place of the small-wheel 17/14 combination.