Oil changes in new cars are now advised every 10,000 miles......is the motorcycle oil so bad that we need to do oil changes more often? OR the motorcycle engines so bad that they kill the oil....

Just being inquisitive.....

 

I'm curious, too. Now, there's oil that they claim only needs changing yearly, or so says 3" Kevin Harvick.

 

Amsoil has had 25K mile or 1 yr oil for years. Mobil 1 is just jumping on the band wagon. I think the thing with air cooled engines is they just run hotter and oil breaks down quicker. I run Amsoil in my '14 Limited and change every 5K. I've never run an oil analysis to see how the oil is at change.

 

I heard another issue is oil filter must be designed for it.


wanted to do a skip on my cars oil filter,so did some searches. I never skipped it cause the cheap filter was always filthy

 

I know a guy that never changed his oil, but he drove so slow. Always Ford's

Not only the heat but the roller bearing's are hard on oil.

 

There was a good article in our local paper about this a few months ago. It claimed the longer intervals between oil changes comes from a battle between car companies about who's vehicles have the lowest maintenance costs. The article said you should be changing the oil when it gets dirty and not waiting until the oil is going to start to breaking down. It went on to say conventional and synthetic oils get dirty at the same rate so there shouldn't be longer intervals between changes using synthetic. The author of the article was no fan of the once a year oil.

 

I think a air cooled engine is harder on the oil.

 

The temperature of a liquid cooled engine is thermostatically controlled, the coolant will run around 220 degrees summer or winter. In an engine that is well temperature controlled, the parts can be made to closer tolerances. One of the benefits is less blow by.

An air cooled engine must be engineered to cool adequately under adverse conditions, slow speed, high ambient temperature. At other times closer to "ideal" conditions, it is "over cooled". Consider a mid summer Las Vegas traffic jam, practically no air flow and 100+ air temp. Oil near 300 degrees would not be unusual. To accommodate a greater temperature range , air cooled engines are built a little bit "looser" than liquid cooled engines. There will be more blow-by in an air cooled engine. Blow-by will contaminate the oil with combustion by-products, including water, sulfuric acid if there is any sulfur in the fuel, combustion soot, and any unburned fuel. Most of that will evaporate at operating temperature, but the soot accumulates. So, especially in summer, we cook the oil and we pass more combustion contaminants into it than a liquid cooled engine. Oil treated like that is ready to be changed at 5000 mile intervals .

Years ago, before oils were so highly developed, 50 hours between changes was recommended. 50 hours at 60 mph comes out to 3000 miles, a fairly typical oil change interval in the past. With better oils and engines, 100 hours between changes was acceptable. That happens to work out to 6000 miles between changes for the theoretical average of 60 mph. 5000 miles at 60 mph works out to 83.3 hours between changes, sort of a compromise between 50 hours and 100 hours. Next, how to build a watch...

 

One good reason is that air cooled engines run hotter. Heat destroys oil over time. 5K is only possible now because of the improved engineering of oil.

 

Occasionally I like to look at decisions in light of risk vs reward. When risks are potentially high and rewards low, I go for the conservative option. I change my synthetic oil at 3000 mi intervals regardless of whats recommended. Its only oil.