I think as long as you replace youre oil at a regular basis you will be fine, many like myself change the oil under 2k so using synthetics are a waste of money with no real gain.FD motors are not failing from a lubrication problem so it dosent matter what oil you are using, I would be more concerned with the dreaded o-ring failer.

 

I use Redline 15-40 ...

no problems so far.

 

What is the best source of Red-Line?