Dirtbikes are subject to severe operating conditions, particularly in competition. High engine temperatures can lead to short-term power losses, premature oil breakdown and even mechanical failures. Not good.
Fluidyne Powersports claims its U.S.-made radiators will increase the cooling capacity of any four-stroke European or Japanese dirtbike by 35-50 percent and reduce engine operating temperature by 30 percent. Cores are brazed, aircraft-quality aluminum with CNC-machined filler necks and mandrel-bent, beaded hose connections. All joints and seams are TIG-welded. Caps are stainless steel and rated at either 16 or 21 psi, depending on the application.
Associate Editor Mark Cernicky tested the Fluidyne radiators on his Honda CRF450R dirt-tracker. A set for that model retails for $500, just $28 more than OE parts. The Fluidynes hold 36 percent more fluid—820cc vs. 603. They are also 25 percent thicker (40mm vs. 32). These gains are offset by a 2-plus-pound weight increase.
Cernicky says his CRF never overheated while idling on the starting line, and the beefier radiators kept his Honda cool when running wide-open around a mile. Handlebar-tweaking lowsides along the way didn’t damage either radiator. Cernicky also sampled a second set of Fluidynes on a Suzuki RM-Z250. Twenty minutes into a 100-degree-plus moto at nearby Pala Raceway, a stock RM-Z needed clutching and even a downshift to climb the tallest hill at speed. The Fluidyne-equipped bike ran crisply, no clutchwork or shifting needed.
Money well spent to go the distance.