I am running a 2007 RXP with similar mods to the Riva stage 3. Ski has done around 110 hours most of them have been on freshwater.

Ski is running perfect at this time with no known problems. Oil changed every 25 hours and I have had the ski for the last 2 years/95 hours.

From what I see most engine problems seen to come from a dropped valve or the oil seal blowing in the S/C blowing and oil then going in to the intake etc.

S/C has just had full rebuild so that should be good for anther 80 hours. At what point would you pull the head off and change the valves to be on the safe side. Also if I was to change the valves what would you recommend I fit or is it just time to bite the bullet and strip the full unit down at the end of the summer this year when ski will have around 170 or so hours on it.