You guys are going way out there on this filter engineering. Have you ever seen a 650 wear bad due to
lubrication shortcomings ? Have you seen bearings, rods, pistons wear out for the same reason ? ? .
The 650 engine is basically a bulletproof overbuilt design. The shortcoming of the sump screen is that
Yamaha built the 650 without a crank oil dam so the screen gets the full force of the pulsing oil whipping off the crank
and this force eventually breaks the screen. The sump screen was meant to catch the big chunks from getting to the side case
oil filter and the oil pump. Fuji of Japan was the builder of Fram's filters in Japan and the factory owner made
the improved screens for Mike as he was a friend and did it as a favor. Fuji Japan has just built a subsidiary factory
in Taiwan so expect the price to come down soon. If you want a better side case filter use the Heiden/Lalonde
filter cooler with the Honda XT/TT paper filter ($4.20 ) and other than that cooling of the oil is all you need for dramatic
improvement. Big fin cylinder, an oil cooler, better oil with zinc (ZZDP) like Valvoline Racing 20W50 all will also help.
Joseph