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Hi everyone,

I am in the process of putting the motor back together and I need to know degree specs for the rotary valve. I found somewhere that it is 135 and 64 but the edges are a good 1/2" inch from the marks.
 

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Discussion Starter · #4 ·
So do I try and get the two marks as close as possible to the valve edges? Like I said and I am a good 1/2 inch away from both of them.
 

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Here is a video of a lady doing rotary valve timing on a seadoo engine same process applies to your engine only you need to use the degrees for timing that your engine calls for.

 

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Discussion Starter · #7 ·
Here is a video of a lady doing rotary valve timing on a seadoo engine same process applies to your engine only you need to use the degrees for timing that your engine calls for.

In the video she is only showing the opening timing (147) but not the closing. I don't understand. I know where to mark the 135 for my motor, but I do not know where to mark the 64.
 

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You shouldn't need the closing unless its desynchronized. Did you mark the brass gear vs. rotary valve gear on the shaft? Did you also mark the rotary valve (brass gear) in relation to the meshing of the worm gear of the crankshaft with mag side at TDC before you took it apart? If not its desynchronized. In that case you will need the closing as well. I will assume you degreed the opening (135) measuring up towards PTO side, to find the closing move your degree wheel's 360 degree position to the top of the mag side inlet hole rather than the bottom side that you used to find your opening, MAG piston remains at TDC, mark your (64) this mark will be down below the mag inlet port moving toward PTO side. The rotary valve plate should line up on or +/- 4 degrees of your two marks if it does you are good that's the allowable tolerance out +/-4 degrees although you want to be as close as possible the closer you are with this the more efficient the engine will be. If it's more than that you will need to take the case apart in order to move the brass gear on the rotary valve shaft in relation to the crankshaft worm gear,the opposite direction by about 5 splines for each one degree of desynchronization make sure to note the position of the rotary valve gear when the brass gear disengages from the worm gear of the crankshaft at removal of rotary shaft. From there turn the rotary valve shaft left or right accordingly then reinstall.
 

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Mine was easy. Get the mag on tdc and there should be a mark on the case. Line the edge of the valve with that mark. Good to go
 
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