If you're keeping the stock springs use 15w. It will help a little. To really keep the front end from diving though you'll need better springs, 0.90s in your case. With those you should use 20w oil.I'm ready to replace some fork seals on my '02S, but i'd like to add a heavier weight oil, can i keep the same damper rod but switch my oil? i'm about 210lbs. and i'm trying to keep the bike from diving when i use the brakes.