Valve timing

912/914 valve timing is fixed (via gear drive) when the crankcase is assembled, so there is nothing to adjust for maintenance. You can see a photo of the timing mark posted in this forum thread:  https://www.rotax-owner.com/en/rotax-forum/3-4-stroke-technical-questions/4188-timing-marks-on-rotax-912-camshaft-and-crank

Have a look at the IPC ( Illustrated Parts Catalog ) to see complete details of the valve train...

Follow up question.

If the cam is correctly timed to the crankshaft, at what angle, either before or after top dead center, do the intake and exhaust valves open and close?