Have a read of this. I found it quite interesting.
http://www.xs11.com/stories/mcnoil94.htm
Yes very informative.
Found this snippet from the Darwin HOG Chapter June 2007 newsletter
'Checking up on oils the other night and found out Harley oil is now made in Venezuela, owned by Hugo Chavez. (Must have been the lowest bidder.) It was made by Sunaco - makes you wonder what you are putting in your bike, that is if you use Harley oil. Stick to Mobil1 synthetic oil - you can't go wrong'
The info supplied by Sparky confirms that Mobil 1 does have the better viscosity retention of the lot
Relative Viscosity Retention (as a percentage of initial viscosity retained after normal use in the same motorcycle) 0 miles 800mi 1500mi Mobil 1 Castrol Syntec Castrol GTX Honda HP4 Spectro 4 100% 100% 100% 100% 100% 86.6% 78.1% 72.2% 69.2% 68.0% 83.0% 74.5% 68.0% 65.6% 63.9%
(as a percentage of initial viscosity retained after normal use in the same motorcycle)
