IBMcpa

<crotchety old roadracer>

When building race motors for motorcycles, the prevailing logic seemed to be that looser (to a reasonable extent) got you fewer frictional losses, and since you could compensate for any incremental degredation in compression through adjustments in base gasket size, that was the way to go. These were for 2 and 4 stroke motors that were rebuilt in the range of every 300 odd miles (2 stroke) to seasonally (4 stroke.)

</crotchety old roadracer>

suterusu

I use Mobil 1 synthetic 10w30. The benefits for synthetic oil are more for "race" oriented cars. If you just street drive and casually do some spirted driving, then dino oil will be fine.

For filters, I use JDM (bought from Spoon in Japan) Honda HAMP filters for the Honda Logo (the small green ones). Supposedly the smaller filter increases oil pressure slightly, and I usually put a hose clamp around it to keep it from expanding during race use. Both ideas are talked about by Ichishima (owner of Spoon). I've done this since my first Honda, and have used Honda HAMP filters on my last two cars.

-Andrew