FORGOTTEN MOTOCROSS TECH: GAS CAP LOGISTICS

One of the newest weird gas cap layouts is the current Yamaha YZ450F design that is hidden under a flap in the front of the seat.

Motocross history is filled with examples of creative ideas that were heralded as groundbreaking, but, because of the rapid rate of change in development, sank into the swamp of forgotten technology. Although some ideas are best left abandoned, others were truly innovative (if not ultimately successful). MXA loves to reveal motocross’ tech trivia. Do you remember this idea? Weirdly placed gas caps.

ATK positioned its gas cap high on the right side of the tank with the spout aimed at an angle to make it easier to pour the gas in. The decal on the sidepanel says “250,” but this is a “406.”

Lito moved their flip-top gas cap off the centerline so that it wouldn’t interfere with the leather strap that held the tank on.

A gas cap is a simple device. It is understood by anyone who ever drank from a sippy cup or owned a lawn mower. But not all gas caps are created equal. Take the 1961 Lito as an example. Lito moved its gas cap from the centerline of the tank to the right. Why? Because the gas tank was held on by leather straps that ran down the centerline.

The 1962 Husqvarna 500 four-stroke used a threaded-on cap mounted in the middle of the metal strap that held the tank on.

By the same token, the 1993 ATK 250/406 gas cap was moved as far right as possible and angled at 30 degrees to make it easier to pour fuel in. The front-mounted downdraft throttle bodies of the current Yamaha and TM engines required unique solutions to the fact that the airbox is where the gas tank used to be.

TM used a NASCAR-style gas cap position on the right side panel (just below the edge of the seat), near where the gas tank was located.

TM copied race cars with a side-mounted gas cap, while Yamaha hid the gas cap under the front of the saddle. The weirdest gas cap position of all was on the 2011 Husqvarna TC450. It was mounted in a cutout in the TC450’s seat (back by the rear fender).

In 2011 Husqvarna also tried to get their gas cap closer to their fuel tank, which was under the seat, so Husky put a notch in the back of the seat and aimed the gas cap rearward. It was possible to land on it over jumps.