1985-2004 KX500 “phi” HV Impeller and gasket set combo


The OptiFlosm KX500 “phi” HV Impeller, another must-have item KX500 engine.

There are only 3 ways to add extra cooling to your KX500:

  1. Bigger frontal radiator area. Not going to happen in the confines of the KX500 radiator shrouds and thicker radiators only slightly delay the inevitable
  2. Cooler air going through the radiator. Strictly subject to the air temperature your riding in.
  3. More Coolant Flow. This is where MSV Racing’s “phi” High Volume KX500 Impeller works its magic!

Rigorous flow bench and real-world MX race testing validated the MSV Racing’s “phi” impeller performance.  Machined from 7075 T6-511 Aluminum for durability and stress resistance, the “phi” impeller dramatically improves your KX500’s H2O cooling and pumping performance over OEM, Frank’s MX, and AS3 impellers, totally dominating the competition!

The “phi” KX500 impeller vanes are computer-designed using “Golden Ratio” proportions based on the KX500’s H2O pump housing. This is in addition to closer tolerances between impeller and housing offer +1.2  average GPM more coolant flow. This increase in flow reduces the cycle time between the engine and the radiators allowing more heat removal quicker, lowering head and coolant temperatures up to 18*f when you need it most!

Remember, horsepower/RPM = heat. Preventing your engine from heat soak is the KEY to building and maintaining maximum engine performance. The more efficient the engine’s cooling system, the more heat (horsepower) it can handle.

Whether you’re racing Outlaw Karts, GNCC, Hill Climb, Sand Drags, SuperMoto, or MX. Railing tight single track, sand dunes, or just love the latest KX500 impeller enhancement. Trust MSV Racing’s “phi” Impeller to help put you at the head of the pack!

(Look at the pics and check out the data. No other KX500 parts company will show you the proof they are the best. It’s the MSV Racing way!)

(Mino, Frank’s MX, and AS3 are the SAME over-sized K500 impeller with spacer)

Note* To ensure ease of installation each impeller comes with an H2O pump cover gasket set for a seamless install.

Additional information

Weight .050 lbs
Dimensions 4 × 4 × 4 in



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Natural Aluminum


5054 T651 Aluminum

5 reviews for 1985-2004 KX500 “phi” HV Impeller and gasket set combo

  1. tribalbc (store manager)

    Put this on my kx500 snowbike. Very impressed!! Saw a temp difference of 40 to 50

  2. Douglass B. (verified owner)

    Jason’s Impeller design keeps both my CR500 and KX500 cool in the AZ Deserts. A temp gun on the radiators shows a considerable cooling over stock.

  3. Ursilly (store manager)

    I received the package quickly. impeller definitely makes the bike run noticeably cooler!

  4. freundlichertaxifahrer (store manager)

    Top-notch part, offering great tuning at a fair price.

  5. Doug Haas (verified owner)

    Price was good and competitive.

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48 in stock

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(5 customer reviews)