I ask my local dealer, what is the standard shock oil. They tryed to look it up but could only tell me the weight, think it was 2.5. I like the bikes suspension so would like stock oil, so it will stay the same. I have 01 and s1 fork oil left over. I am going to change the oil and re-gas myself. Bike has done 130 hours. Just replaced piston, plug and checked shims, had not moved in 60 hours, love this bike. Hope it will last till I can pick up a slightly soiled 2010, when 2011 come out.