Boyesen Supercooler Kit - Product Of The Week

A redesigned water pump impeller and impeller cover for motocross and off-road bikes

Cover and impeller
Each make and model has it's own design. This unit is for our 2016 Honda CRF250R.Photo By Sean Klinger

Boyesen Supercooler Kit for 2016 Honda CRF250R

$189.95 standard colors

$195.95 spectra colors

As temperatures start to rise (at least in the west) we are taking a look at the Boyesen Supercooler Kit for a 2016 Honda CRF250R. This kit replaces a bike’s water pump impeller and impeller cover. Although it has been on the market for a while, Boyesen has new Spectra colors to make your bike stand out even more – different colors are available for different bike brands. Back 2010 we bolted a Supercooler Kit to our WR450F and did a full test. Read on to see how it worked.

“Keeping your bike cool can be a tall order under some circumstances. Boyesen's Supercooler Kit might just make the difference you need. Boyesen took a look at the stock cover and impellers on most dirt bikes and improved them by increasing their pumping capacity and smoothing out the flow of coolant through the pump. First, Boyesen redesigned the impeller so that it moves more liquid by making the impeller blades almost twice as tall as those on the stocker. Each revolution of the impeller moves more liquid at any rpm. Since there's no thermostat to control coolant flow in a dirt bike engine, the water pump determines how the coolant moves through the engine and on to the radiators. At rock-crawling or slow woods speeds, low rpm can cause overheating. Having more coolant moving through the system faster can mean the difference between running hot and boiling over.

Inside look at impeller cover
The inside surfaces of the cover are hydrodynamically designed for more efficient coolant flow.Photo By Sean Klinger

Another problem with water pumps is cavitation, which occurs when naturally forming air bubbles in the coolant are met with turbulence inside the pump. In a water pump, cavitation can actually reduce pump output by half or more. To reduce this, Boyesen has redesigned the interior of the pump cover to accept a larger impeller and to eliminate any sharp edges and corners that can contribute to cavitation.

With the Boyesen setup on the WR we immediately noticed a difference. The Factory Effex heat tapes we use on many of our bikes showed at least a 10-20-degree lowering of operating temperature and an ability to maintain it without wild fluctuations, especially at low speeds. We've subjected the WR to the MX track, technical woods single-track, hillclimbs, desert riding and everything in between. Since switching to the Boyesen unit more than six months ago, we haven't had to add coolant to our WR once and haven't seen any change in the coolant overflow tank level. Installation was easy, and the cover is available in black, magnesium or silver vein finishes.”

Orange cover
This orange finish might be attractive to a certain Austrian bike brand owner...Courtesy Of Boyesen
Blue cover
This cover is blue and so are Yamahas. Coincidence?Courtesy Of Boyesen
Black cover
If your bike strays from the traditional color schemes, black goes with anything.Courtesy Of Boyesen
Red cover
Honda owners will enjoy this rosy hue.Courtesy Of Boyesen