Do you remember Gyro Gearloose? He was an anthropomorphic chicken created by the Walt Disney Company who appeared in the Scrooge McDuck comic-book series. Gyro was the town of Duckburg’s most famous inventor. Because his inventions were rarely successful, the name Gyro Gearloose has become synonymous with any inventor with a crazy or crackpot idea. Motocross has had more than its fair share of Gyro Gearlooses — some amazingly successful and others forgotten. MXA presents the latest installment in its series of weird and wacky inventions.
Boost bottles were vacuum-controlled chambers that were connect after the carburetor, but before the reed valve. The suction of the fuel passing by the boost bottle orifice on the intake stroke allowed the boost bottle to suck up excess fuel when the reed valves snapped shut. This extra fuel could then be mixed with incoming fuel on the next intake cycle. It started out as an aftermarket product, but even Yamaha realized that it helped the midrange and put the Yamaha Energy Induction System (YEIS) on its production two-strokes. There is no reason why it wouldn’t still work today.
Boost bottles came in all shapes and sized. Engine tuners, like Pro Circuit’s Mitch Payton, spent a lot of time trying to find the perfect volume. This Pro Circuit Husqvarna has a special manifold for the reed block to incorporate the tube. The boost bottle is strapped under the gas tank.
The trickest boost bottle ever was on Andy Jefferson’s Pro Circuit Husqvarna. It was built into the aluminum gas tank.
The factory teams also used boost bottles. The rectangular Yamaha works boost bottle was hose clamped to the OW’s remote shock reservoir.
Although you might mistake this for a boost bottle, it is in fact an auxillary gas tank on a factory Kawasaki. It mounted where the petcock would normally go (and the petcock was mounted on the bottom of it). Back in the day, AMA National motos were much longer than they are today and the gas tanks were not always capable of going the distance. The AMA later banned auxillary gas tanks.
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