M8 Cooling And Venting Solutions

Since the advent of the Twin Cam engines, Harley-Davidson motorcycles have a history of running hot. Two factors come into this; neither of which is solely the fault of the Motor Company. The first of these is the plethora of government dictates on emissions which strangle much of the power – and the second one is what we, the owners, do to our motorcycles.

- Doc

The strangling can be addressed in various ways, beginning with freeing up both the intake and the exhaust and with appropriate finetuning to the Engine Control Module (ECM). Adding better flowing heads with larger valves is another step as is selecting a higher performance cam (or cams) and removing the catalytic converter.

But of course there is a downside to these engine modifications also, and that is they are usually done to increase both horsepower and torque. So we seek higher compression ratios also and the net effect of the combination of these changes is increased heat – increased radiant heat – which is felt by the rider.

Then, in the bagger world, we have the air flow reduction created by fairing lowers, which can be quite substantial. Plus if we add in the weight of a beefy rider and his voluptuous other half, and things can get really hot.

Now the big problem with air-cooled engines is that they need air flow to produce cooling. Oil coolers do not do much when there is little or no air flowing over them such as in heavy traffic, stop/start conditions. Here is where fan assisted cooling can play a role.

Well a mate of mine, who was very pleased with his unit, suggested I take a look at the ThunderMax Oil Cooler fan and so I did, and because I liked what I saw, I booked my bike in at Adelaide Harley-Davidson Bike Works to have one installed.