§ 02 / Brand
BOYESEN
Boyesen builds intake and cooling kit that does real work. The reed valves clean up throttle response off the bottom; the supercooler water pump impellers shift more coolant per revolution and hold temperature on long motos. Ignition and clutch covers add proper boot-wear protection without the weight penalty of billet. Pick by engine displacement and model. Filters narrow it down.
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Refine your fitment →BOYESEN — frequently asked questions
Common questions, straight answers. No fluff.
- Inspect every 20 to 30 hours. Look for fraying at the tips and a petal that no longer sits flat against the cage. Either symptom means replace them. A tired reed costs you throttle response long before it actually breaks.
- Yes, in the conditions where it matters. The high-flow vane shifts more coolant at low RPM, which is exactly when a stock pump struggles. Slow technical sections, deep ruts, sand work, summer trail rides with the fan never quite catching up. It bolts to the factory mounting points and runs the OEM gasket, so fitting is a coolant drain and a torque wrench rather than a workshop afternoon. You will not feel it on a fast moto. You will feel it on lap six of a hare and hound.
- Yes. The covers are machined to OEM mating-surface specs and run the factory gasket. Fit the same bolts to the same torque values. The powder coat shrugs off chain lube and pressure washer abuse better than the original cast finish.
- They do. The top petal cracks open early for clean off-idle pull, then the bottom petal lifts as revs climb to feed the engine at full song. The result is a wider usable powerband, especially noticeable when you are short-shifting out of corners instead of wringing the bike's neck.
- Seat the impeller square on the shaft and check the pin is captive before you close it up. Test-fit the housing against your skid plate and frame rails. Drain the system fully, refill with fresh coolant, then bleed properly and run a heat cycle before you trust it on a ride.
- Denser aluminium alloy, thicker wall sections than the factory casting. A shift lever pushed into the case in a crash will usually dent the cover rather than crack it. That is the difference between finishing the moto and watching oil pool under your boot.