Polaris Pro-R 600/800 CFI Airbox Mod
A great modification to get more air and more power is to modify your airbox. Pull the cover off the box and inside you will find a shelf like the one pictured below. Remove this shelf and replace it with our BMP High Flow Pro-R Shelf. We found that holes in the top side of the shelf (shown below) worked the best, gaining 3 horsepower through mid to peak. Some may think more is better and want to add additional holes in the bottom of the shelf. We advise not to do this! This creates a strange wave flow in the airbox and which causes the shelf to only produce 1 HP over stock. Removing the shelf altogether gained 1.5-2 HP. No fuel modifications needed on a stock or slightly modified machine. Just cheap and easy horsepower! Click the picture below to purchase this airbox shelf.
Polaris 800 CFI Low Compression
Do you have a Polaris 800 CFI snowmobile? Be sure to do a compression check! These motors have quite a bit of rod angle and are known to wear out rings and pistons fast! Your motor should have at least 125 PSI of compression (make sure you hold the throttle wide open!) on a known good gauge. We have seen many sleds around the 2000 mile mark with low compression that do not make peak power. If you are around this mileage, keep an eye on your tachometer as this is a good indication of a weak motor. A motor low on compression will be a few hundred short on peak RPM.
FIX IT! Now we have our Durability Kit which uses a cylinder spacer and taller pistons with rings spaced slightly further apart. This helps the motor be more reliable and even gains 5-6 HP with no fuel controller! See the Durability Kit by clicking HERE
Polaris 800 CFI Oil Pump Adjustment
Yet another problem easily fixed with the Pro-R 800 CFI!! They run very lean on oil from the factory which can be costly, especially when running mods where you are adding extra fuel. We even recommend pre-mixing your fuel at 100:1 in addition to this adjustment. We recommend turning the pump up 3 full turns on a big bore, 1.5 turns when adding fuel with a controller, and even 1 turn for stock machines. Here is a great how-to video on how it's done for big bores!