Seadoo Rotary Valve Repair and Clearancing

This video shows how to repair the Rotax rotary valve cover according to the factory manual specifications. In this video I show you how this is done on a lathe. The cover is resurfaced and valve clearance is reestablished to 0.012 inch per manual specifications. Anyone interested in this service please go to crankshaftandc... or email [e-mail].

[@abhvgas]

hello. my question is this. on a 717 engine, what is the no. to be within spec. also when i take a measurement is it between the cover and the block without the rotary plate installed? ive seen people measure between the rotary plate and cover. so im am confused of what to measure.

[@atomictim6422]

As I am a rookie on the subject, may I ask what performance issues/symptoms are you fixing by resurfacing this plate?

[@crankshaftandco]

The rotary valve must close on the charging stroke or you loose some of your air fuel mixture and have less compression. Same as a reed valve leak. You will loose power and ultimately have trouble starting the engine.

[@atomictim6422]

@@crankshaftandco Thanks so much for your info! I'm in process of rehab'g new to me ski and I know serious groves on the the cover. When I tested after carb rebuild it was def low on power and felt almost like one of the cylinders was cutting in/out- do think that cover plate could be issue? THX again.

[@edwardg9695]

What about scoring on the crankcase side? Did you surface that somehow?

[@crankshaftandco]

No the block doesn't get worn. What is apparent is the compression force pushes the vane out against the cover plate and wears against it.

[@edwardg9695]

@@crankshaftandco My block and valve cover both have scoring. I guess carbon deposits were spun between the valve and block. I was wondering if you had the same and polished or machined it.

[@crankshaftandco]

@@edwardg9695 not really you'd have to ship the block too.

[@crankshaftandco]

@@edwardg9695 HI, I recently made some fixtures to mill the crankcase to resurface it also. I will post the video soon. Let me know if you need this service.

[@JOSERGMMXX]

just wondering if is best buy the cover .cause maybe 🤔 your labor is about same cost.though