A reader asks: I bought a used 1998 Heritage Softail Classic with 47,000 miles. As far as I know, only mineral oil was used in this bike. I’ve heard good things about using AMSOIL Synthetic 20W-50. Is there any problem with switching to synthetic oil in an older engine? Will it leak or use oil?
Our answer: It is certainly acceptable to switch to synthetic oil in an older Harley-Davidson engine. If the engine is mechanically sound, there should not be any problems. Synthetic oil can be used in older transmissions and primary chaincases as well.
Despite its age, your engine is not “adapted” to only conventional oil. It does not matter if the engine was broken-in using mineral oil. The switch to synthetic oil can take place at any time.
Once converted to synthetic oil, the motorcycle will now have improved performance on a number of fronts. AMSOIL V-Twin 20W-50 lowers friction and withstands extreme heat. Here are the improvements that our customers observe.
- Lower operating temperatures
- Improved throttle response
- Increased gas mileage
- Lower volatility which fights oil consumption
- Smoother shifting when used in the transmission
- Easier to find neutral when used in the primary
Will synthetic oil cause leaks or consumption in an older motorcycle engine? If the seals are sound and the engine has not had serious oil consumption problems, all should be just fine. AMSOIL V-Twin 20-W-50 has a greater resistance to volatility over regular motorcycle oil. This means less oil usage on very hot days.
In conclusion, switching to a top-tier synthetic oil like AMSOIL is the most cost-effective upgrade you can perform on your Harley-Davidson motorcycle. This is true of brand-new models or older bikes.
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