About

About the fan unit

Two high powered fans each blow over 180 CFM (cubic feet per minute) – that’s over 360 CFM in total. These are the most powerful 12v fans of this size (92x92x38mm) I could find. They spin at 13,000 rpm and generate 74 dB(A), quieter than most Harley exhausts. The fans blow ambient air onto the cylinder heads, through the fins and air passages. This is smarter than trying to suck hot air away from the heads and through the fans.

The mounting bracket is precision machined by a CNC unit. It is shaped to hold the fans at 22.5° from vertical to align to each cylinder in the 45° V twin Harley Davidson engine design. The single mount on the horn bracket is simple and convenient. The bracket is made from a HDPE (high density polyethylene) plastic. A plastic bracket helps isolate engine vibrations from the fans. HDPE is heat resistant and has proven to keep its shape over use.

About the assembly process

Each fan unit is hand assembled in Australia. Each unit is tested after assembly before shipping.

The fans are carefully sealed to protect against water and dust. (They do not have an IP – intrusion protection – rating, but have proved weather resistant in testing.)

The wiring is cut to length, connections and a 10amp fuse fitted, all protected with black heat shrink.

About the design and development process

I developed these engine cooling fans after trying to find a way to keep my 2010 Harley Davidson Road King running cooler.

I bought this bike as a demo from a dealer in Sydney Australia. It came fitted with a Screamin’ Eagle Stage IV kit. http://www.harley-davidson.com/store/se-103-ci-performance-stage-4-kit This provided really pleasing power, but did run hot and noisy.

After just 39000 kms and just a few months out of warranty, a tappet bearing seized and threw metal all through the engine. Devastating.

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After a rebuild by the dealer (parts at half price but I still had to pay for labour), I became very sensitive to heat and noise. Understandable I think.

I fitted a JAG oil cooler with thermostatically controlled fan. This works well, but in traffic the engine still gets hotter than I’d like.

I started surfing the web for other solutions. There are a number of aftermarket cooling fans on the market, some with a lot of hype on their websites. The idea of a cooling fan is sound, but the cost of getting one to Australia put me off. A$400-$600 + shipping seems too much for what is fairly simple technology.

So I set about building some of my own. My first thought was to use a marine bilge fan because they put out high air flow. But these were difficult to fit and would be unsightly.

WP_20151120_17_16_11_ProEventually I found some high powered fans at a reasonable price and designed a mounting plate to direct the airstream directly onto the centre of each head. It took a few (ugly) prototypes to get the mounting plate right, but the result is simple and effective.

It’s likely I’m not the only person with a  Harley® that runs hotter than you’d like. So, I’m making these engine cooling fans available to anyone who wants a simple, cost-effective solution.