Polaris Announces 800 H.O. Cleanfire Engine Updates for MY2018
Polaris has announced a number of upgrades to MY2018 sleds, including several noteworthy 800 H.O. Cleanfire Engine updates and well as a few other key refinements.
800 H.O. Cleanfire Engine Updates
The first update is a new thermostat, which will lower operating temperature from 125°F (51.6°C) to 110°F (43.3°C), which will improve the engine overheat margin as well as provide more consistent engine operation. The thermostat also increases the main circuit flow by 12 percent which increasing bypass flow by 9 percent.
The new MY2018 800 H.O. Cleanfire Engine thermostat.
The thermostat from MY2017 and earlier 800 Cleanfire Engines.
Side note: The new thermostat could be potentially be retrofitted on 2015-2017 800 HO engines, however more is needed than just the thermostat. The physically larger thermostat would also require a new head, cover and thermostat housing for installation.
In addition, a new exhaust gas temp sensor (EGT) with an improved connector and a more durable sensor element should provide over 200 percent life improvement. The new EGT is matched to the electronic control unit (ECU).
Furthermore, sealed cross-shaft cavity crankcases provide additional lubrication and increased durability on both 600 and 800 H.O. Cleanfire engines. Also, an improved MAG end seal works better and should increase durability on 600 and 800 H.O. engines.
Other notable Polaris upgrades for MY2018
RMK Monotube Shocks will feature all new valving for MY2018, with “Hi Flow” Walker Evans pistons on the Front Suspension and Rear Track Shock that delivers less bottoming in the big bumps while maintaining a supple feel on the trail.
The SKS will have an upgraded Series 5.2 146″ x 2.25″ track. The new track has been refined based on the results of the modified Series 5.1 track used to dominate the RMSHA circuit last season. The Series 5.2 track is claimed to provide great traction on- and off-trail, while offering excellent durability.
The final update for Polaris MY2018 sleds is that the 800 Assault Switchback will be available in-season next winter with electric start and the Series 4 2.0 track.
— MS
