Posted by Ray Toews on July 05, 2003 at 07:05:04:
In Reply to: Re: I use this oil -- but I'm losing it! ADVICE? posted by Bob on July 03, 2003 at 16:25:28:
I have an 02 with 14k kilometers and use only straight grade oil, W30.
Multigrade oil has a polymer added to make it thicker when hot and thinner when cold. This polymer is not a good lubricant.
Synthetic is better oil because it is essentially a multigrade in that it doesn't change viscosity with temp change. It's main claim to fame is that it burns at a higher temp so doesn't burn(charcoal) when it touches hot engine parts.
Multigrade oil was developed because we are too lazy in winter to warm up our engines before starting.
This is not a problem with motorcycles as they are only driven when the temp is warm.
An engine generally runs at close to the same temp, winter and summer so the oil needs only be one viscosity.
Read http://www.americanmotor.com/news.cfm?newsid=2215 for more info.
Ray