tech notes return of fourcylinder sled

Amsnow is now

Some would argue that more cylinders mean more weight, but if you are up against Yamaha’s 4-stroke turbo you should still end up lighter with a 2-stroke triple 1000cc or even 1200cc. Four-cylinder engines are nothing new; Arctic’s King Cat still competes on the Vintage Oval circuit. Yamaha’s V-Max 4 was a hugely popular sled in spite of its inline design and wide body. I never heard anyone complain about V-Max 4 styling. The biggest problem with the V-Max 4 was its long crankshaft which acted as a gyroscopic stabilizing force in a straight line, but made it harder to handle in tight turns. This made it hugely popular for straight-line drag racing and speed runs, where highly modified 1000cc V-Max 4 race sleds produced close to 300 HP.

¦ Less with more
There is another alternative to an inline four that solves both the weight and width problem, and that is a V-4. A V-4 based on outboard technology need only be two inches wider than a twin as the rods sit on the same pin separated by a divider plate with sealing rings. A 90-degree V-4 ends up being lighter than a triple by 30 pounds.

We built such an engine in the early ‘90s and it was a light, compact package with a very smooth power delivery that was easy on clutches and belts. With the short crank and low gyroscopic forces, it was also quick handling in the turns. We raced them in drag sleds as 800cc and 1000cc motors. After a usual development period, the engine ran reliable in both the sleds. In the drag sleds it ran 12 seasons without a problem.

In old-school engineering, we selected the power source that we wanted, then the chassis and suspension were designed around it. As a last step, the stylist came in and wrapped it in a nice package. Styling was never the first consideration back then, so form followed function. That was exactlyπ what Bobby Unser did over 45 years ago when he designed the first IFS suspension that would allow a large “race-winning” engine with plenty of room for triple pipes.

Personally, I don’t feel “skinny noses” have made the sleds look any better, but they have made sleds harder to work on and colder to ride. If a stylist knows what he is doing, he can make anything look good, warm and accessible. Making style first priority is bad engineering.

If a 90-degree V-4 engine would ever get approval in a snowmobile boardroom, we might see a 1200cc version making 250 HP at 8000 RPM. In a light and responsive sled, with appropriate styling and suspension tailor-made for lakes and trails, this would be the ultimate “King of The Lake.” Game over!
  • Like what you read?

    Want to know when we have important news, updates or interviews?

  • Join our newsletter today!

    Sign Up

You Might Also Be Interested In...


Send to your friends!

Welcome to Snowest!

Have a discount code on us.

Discount Code: