The Motorbike Archives

Two years ago everything changed, and changed for the better. Yamaha introduced a very sophisticated machine known as the Mini Enduro. The Yamaha bike looked like a small motorcycle, it had good power, and it was damn near "bulletproof." The kids adored it and the fathers blessed it. Here was a machine, designed for the kids, that freed dad from the chores of keeping a mini-bike operating.

Naturally the Yamaha Mini Enduro sold like the proverbial hot-cakes. In fact it created a new classification of machines. Now, in addition to mini-bikes and motorcycles we have mini-cycles.

One of the newest additions to this rapidly expanding field is from Gemini and it's called the Boss 80. The Boss 80 has all of the features that have made mini-cycles so popular. It has large spoked wheels, the suspension is remarkably sophisticated, the engine produces good power over a wide band, and, most important, the machine looks like a miniature motorcycle. Actually, the Boss 80 is slightly larger than most mini-cycles. Overall length is 70 inches, wheelbase is 48 inches, its widest point (the handlebars) is 34 inches, overall height is 38 inches, and seat height is 29 inches. A 17-inch wheel is fitted to the front of the machine while the rear of the bike carries a 15-inch rim. The front tire is 2.25x17, and the rear tire is 2.50x15. Both tires are full knobbies, rather than the trials universal-type found on the majority of mini-cycles.

One of the obvious advantages of being slightly larger is that the Boss 80 can carry heavier loads, meaning, that more members of the family will be able to get use out of the machine. The obvious drawback of the Boss 80 is that, particularly with that 29-inch seat height, the smaller members of the family will not be able to use the bike.

The Boss 80 is powered by a single cylinder, two-cycle engine with a bore of 47 millimeters and a stroke of 82 millimeters. Total capacity of the engine is 80 cubic centimeters, compression ratio is 8.1:1, and maximum output is 7.5 horsepower. Induction is controlled by a rotating disc mounted on the right end of the crankshaft. A 15 millimeter Mikuni carburetor feeds the fuel/air mixture to the combustion chamber. Lubrication of the engine is accomplished with an injection system which posses most of the positive characteristics common to this form of oiling. The oil pump meters the amount of oil, depending on engine rpm and on the load under any operating conditions, thus forcing the proper amount of oil into the engine at all times. With any form of two-stroke injection oil consumption is considerably improved, carbon build-up is reduced, and excessive smoking from the exhaust pipe is almost completely eliminated. Oil for the Boss 80 injection system is carried in a tank mounted on the right side of the bike.

Primary drive, between the crank shaft and the clutch housing, is by helical cut gears and the power is transmitted to the rear wheel through a 4-speed gearbox. The transmission is extremely smooth in operation and the shift pattern appears to have been designed with the beginning rider in mind. Neutral is all the way at the top of the shift pattern. By progressively depressing the shift lever first, second, third, and fourth gears are obtained. The beauty of having neutral all the way at the top of the pattern, particularly for the youngsters, is that it does away with the need to find neutral between first and second as is common on most transmissions.

The Boss 80 engine is a very willing performer and it's very easy to start. Cold starts are simplified by the enrichening lever mounted on the left end of the handlebar. When the engine is cold you simply swing the lever to the open position, with the throttle closed, and, kick the starter lever one or two times. Invariably the engine will fire.

The chassis on the Boss 80 is extremely rugged. A very large diameter backbone tube passes from the streering head beneath the gas tank and then curves downward to terminate at a built-up structure. A pair of front downtubes are bolted to the steering head gusset, and pass beneath the engine to terminate at the aforementioned box structure. The sub-frame consists of an upper loop which supports the saddle and rear fender and a pair of diagonal stringers which provide torsional rigidity. A sturdy bash plate welded to the cradle tubes protects the underside of the engine and helps keep the tubes parallel. Constructed of tubular stock, the swinging arm is well braced at the pivot point to prevent flexing. Many of the welds on our test machine were quite sloppy and could have used some "cleaning up," however, the glossy black enamel which covered everything was very well applied.

Suspension on the Boss 80 is quite good. The rear shocks are hydraulically damped and are capable of meeting demands put on them by the small adult. With a youngster in the saddle the rear suspension works just fine. Much the same can be said for the front suspension. With a mini rider on the mini saddle the front end will begin to make noise, particularly, when the machine is forced over rough terrain.

From the standpoint of styling it's difficult to find fault with the Gemini Boss 80. The headlight and speedometer are well integrated, however, the taillight/license plate holding assembly looked like the proverbial afterthought. The machine has more than enough engine, it's a good looking bike, muffling is excellent (though we do wish the machine came with an approved spark arrester), and overall finish is good. In its stock form the Boss 80 is a good example of the current state of the art in the mini-cycle field. In modified form it has already shown itself to be a force to be reckoned with in mini-cycle racing associations. The Gemini Boss 80 is a good choice for the youngster caught between mini-bikes and motorcycles.■