Owners of Polaris models fitted with plastic airbox fittings (that the carb vent lines are attached to) want to verify these fittings are not broken. If they are broken or cracked, the carb vent lines and float bowls will not â€œseeâ€ the proper airbox pressure, resulting in a rich fuel delivery due to the increased float bowl pressure. The machine may not always reach peak operating RPM, fuel consumption will be higher, and overall performance will be sluggish due to the inconsistent float bowl pressure and resulting fuel delivery.
Damage to the plastic fittings normally occurs when the vent lines are removed for carb service or jetting purposes. If you are lifting or twisting excessively when removing the vent lines from the airbox, the cheap plastic fittings can break rather easily. Ideally, you want to pull the vent line straight out and away from the airbox and twist only slightly to remove the tubing from the fitting.
The best solution is to install metal fittings, replacing the less expensive plastic pieces. Thunder Products (320-597-2700) offers a complete kit of metal fittings, but takes it to the next level. The kit not only replaces the fittings with billet aluminum and brass ones, but adds â€œbalanceâ€ lines so each carbâ€™s float bowl sees exactly the same pressure from the airbox. This will provide a very consistent fuel delivery, sort of a float bowl synchronization if you will.
Polaris Airbox Fitting kits for carbed twins go for $19.95; kits for carbed triples go for $29.95, and are available from many performance shops like Thunder Products, Fett Brothers Performance, or Hi-Performance Engineering.