Boyesen’s Supercooler or Hy-Flo kits for enduro (plus motocross and XC) promise to improve the performance of your bike's water cooling system, helping running efficiency and extend the life of the engine.

Controlling your bike’s engine temperature is essential. In enduro, the cooling system works harder than in any other discipline simply because of the conditions we put it through—covering it in mud, riding through woods, tackling mountains, and getting stuck in rock gardens. Not to mention the fact that we have a habit of riding where airflow is restricted—who hasn’t boiled over a bike, especially on muddy days or in hard enduro?

A working fan, clean radiators, a well-maintained cooling system, and fresh coolant all help, but what about the circulation of fluid around your bike’s engine? If the flow of cooling liquid through your engine were more efficient, that would make a difference, wouldn’t it?

That’s where the Boyesen Hy-Flo kit comes in

Boyesen says Hyperflow Integration (HFI) uses computer technology as the backbone of their Supercooler’s design, focusing on "correcting the inefficiencies and production-based limitations found in the design of stock water pump systems" by improving fluid flow, efficiency, and heat management in your engine.

The reason this matters is that poor water cooling can have a dramatic effect on your engine’s components. In a fuel-injected engine, the problems can be amplified as the temperature sensor detects overheating and sends signals to the ECU to reduce power and protect itself.

Overheating can cause pre-ignition and detonation, which may lead to distorted cylinder bores, potential damage to pistons and rings, and compromised valve-train components. At best, overheating could ruin your race; at worst, it could result in extremely costly repairs.

The Hy-Flo kit might look relatively similar to the stock parts at first glance, but the inlet diameter, interior surfaces of the Supercooler casing, and the impeller design itself are all improved over the OEM parts.

Boyesen should be familiar to you as designers and engineers of various engine components, including induction reeds and engine cases. Simply put, they are best known for specialising in the improvement and upgrade of standard bike parts to enhance performance and longevity.

When it comes to their focus on the water-cooling system of two- and four-stroke carburettor and fuel-injected engines, this attention to detail couldn’t be more important.

Boyesen Engineers are in a constant process of R&D for each make/model/year of machine as they update and to improve the performance of the many factory race-supported teams.

They call it “the best performing water pump system that you can buy” and it’s true to say it is recognised worldwide by factory race teams as a bolt-on engine heat-reduction part.

What’s in the kit? 

1 x water impeller

1 x magnesium cover

1 x gasket

Uses bolts and retainer pins from OEM

Fitment is easy and the process is covered by instructions included with the kit or on Boyesen’s website. It took us about 20 minutes to fit this one to our YZ250 project bike. 

The job includes draining the coolant (a good excuse to refresh the fluid in our bike) and using an impact driver on the impeller. The instructions simply say "remove stock water pump impeller" which is to say check with your manufacturer’s manual which may recommend a lengthier process.

The Supercooler is available for a wide-range of dirt bikes form Japanese and European manufacturer.

Cost: From £240 / $194.95

Contact: www.boyesen.com  

UK stockists: www.apicob2b.co.uk/boyesen