28 Aug Extreme Heat Can Sideline Your Bike, Don’t Let it
The town of Sturgis, SD is the epicenter of biker culture for more than a week every Aug, traffic slows to a crawl. A mile or two later, you start seeing riders pulled over to the shoulder of the road. Some stand idly by their bikes, some push them down the road as the blazing sun beats down upon them. Extreme heat has sideline their bikes.
What often happens, as heat intensifies, motor oil loses viscosity and becomes thinner. The oil can become so thin that the engine loses oil pressure, causing the oil-pressure gauge to bottom out. The rider may notice increased valve-train and gear noise as engine parts clatter together. Any rider worth their salt knows that you don’t run your engine with zero oil pressure, so rider shuts the engine down and sit alongside the highway (or pushes the bike) until the engine cools enough to restore oil pressure.
Air-cooled V-twins get plenty hot on their own, but riding in slow-moving traffic makes it worse. Crawling along barely above idle doesn’t generate sufficient airflow to cool the engine. Add to that, the blazing sun reflecting off the asphalt, and it’s a recipe for trouble. In the lab, extreme dyno-testing designed to create heat, we’ve seen cylinder temperatures in a 2012 Harley-Davidson* Street Bob* as high as 383ºF (195ºC).
It’s up to the motor oil to protect the engine despite the intense heat. Oil becomes thinner as it heats up, and if it becomes too thin, it can fail to form a lubricant film of sufficient thickness and strength to prevent metal components from contacting during engine operation and wearing out. Once the lubricant film fails, it falls on the anti-wear additives to prevent wear. They form a sacrificial layer on components to keep them from contacting. Additives are designed to deplete with time and use and once they wear out, your engine isn’t protected.
Although heat is a bigger challenge for air-cooled engines, extreme heat can also negatively affect liquid cooled bikes, even though they run much cooler. How much cooler? Testing of a liquid-cooled Indian* Scout* in our mechanical lab revealed cylinder temperatures averaged 200ºF (93ºC), far cooler than the Harley running the same test. That’s because a liquid cooled motor relies on a jacket of coolant/ water surrounding the cylinders to absorb heat and carry it to the radiator where it dissipates into the atmosphere. Water/coolant is a more effective heat-transfer medium than air, which you can clearly see in the cylinder-temperature difference between the two bikes.
Even so, engine and oil temperature will still increase along with ambient heat, so it’s just as important to use a good motorcycle oil in liquid cooled engines.
The rate at which oil oxidizes, or chemically breaks down, doubles for every 18ºF (10ºC) increase in lubricant temperature. Oxidation occurs when oxygen molecules attack oil molecules and result in a chemical reaction that leads to harmful byproducts, like sludge and varnish. The faster the oil oxidizes, the sooner it wears out and requires an oil change.
Liquid cooled engines may run cooler and help prevent overheating, but in case you hadn’t noticed, riders are fiercely loyal to their bikes. Their big air-cooled V-twin is an extension of their personality, and they aren’t about to trade it in for another brand just because it’s hot outside.
This situation perfectly illustrates the importance of using AMSOIL products as solutions to your customer’s motorcycle problems. AMSOIL Synthetic V-Twin Motorcycle Oil uses high quality synthetic base oils that naturally resist thinning due to extreme heat and mechanical activity better than conventional base oils. As a result, it forms a thick, strong lubricating film on engine components despite the intense heat. Although any oil will become thinner in extreme heat, riders who use AMSOIL Synthetic V-Twin Motorcycle Oil won’t see their oil-pressure gauges bottom out, providing the confidence they need to keep riding after others have shut down their bikes and started pushing.
With AMSOIL, riders don’t have to buy a different bike, they just have to buy a better motorcycle oil.