New 800 2-Injector Engine

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There are so many new models and features in the 2011 Polaris line-up, it almost seems repetitive to focus on Roseau’s revamped new 800.

However, after testing this engine in the new RMK, Switchback and the improved 2011 RUSH last week in Montana, we’re pretty confident this is the company’s top technical advancement this year. Why? Frankly, the 4-injector Liberty-8 has been a bit of a disappointment to many big-inch Polaris purchasers the last two years and they’re looking for more.

The new 800 uses a single injector per cylinder and it’s located up high in the boost port. This means the lower injector has been eliminated (this one used to squirt fuel downward into the crankcases).

Injector flow volume has been increased to match the fuel supply of the 4-injector setup and the angle of the upper injector has also been modified for better fuel delivery.

The big advantage of using only a boost port injector is there is no fuel, only air, going through the crankcase. This not only results in a cleaner burning engine generating less hydrocarbon emissions but also prevents wash-down of injector oil on the crank and rod bearings.

Oil injector pumps can be set lower and less oil used overall. Even with no liquid cooled cases Polaris claims there are no issues with crankcase heat and the 2-injector mill is expected to live a long, durable life.

We ran the Liberty 800 against the competition’s 800 2-strokes and found it to be extremely competitive. Of note especially is its giant dose of bottom end power when you tap the throttle.

Starts are clean and lean and throttle tip-in is flawless. We’re not sure about oil consumption and gas mileage yet but we suspect this mill will be better than the former one in both areas.

Supertrax Online
Supertrax Online
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