2004 Ski-Doo REV Series Factory Service Manual, Page 117Get this manual
Section 04 ENGINE Subsection 01 (593, 593 HO, 593 HO SDI AND 793 HO ENGINE TYPES)
Maintenance
All Models There are no wear parts anywhere in the system and there are no adjustments to be periodically checkedThe only possible maintenance required would be cleaning of carbon deposits from the guillotine slideCleaning intervals would depend upon the user's riding style and the quality of the oil usedBombardier suggests annual cleaning of the valveIf customer uses lower quality oil, than recommended, more frequent cleaning may be requiredNo special solvents or cleaners are required when cleaning the valveOn SDI models, check if solenoid heating element is still functional once year, the element should be warm after one minute of ridingAt the same time, check if crankcase check valve is still functionalNOTE: Make sure hoses are not kinked or damaged