Rotary valve timing 670

Snow Guy

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I have a 99 670 summit x that I just put a short block in. Would I know if the timing of the rotary valve is off?
Thanks in advance


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CUSO

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I would think that if the cutaway was timed at the factory, then you should be ok.

How does it run/perform?

I have a 99 670 summit x that I just put a short block in. Would I know if the timing of the rotary valve is off?
Thanks in advance


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Snow Guy

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I would think that if the cutaway was timed at the factory, then you should be ok.

How does it run/perform?

Sorry I took so long to reply, got snow to ride it on tonight, it goes ok not great till it gets to about about 6800-7000 rpm then it start to cough and miss.
I had to put the rotary valve on the short block and time it, that's why I think it may be the valve timing.
 

slededjr

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This is from the race manual. If you need clarification let me know.

The wheel they are talking about is a degree whell you would need to time the RV.


Instructions
OPENING: 145� BTDC
CLOSING: 71� BTDC
Proceed as follows:
� Turning crankshaft, bring MAG side piston to
Top Dead Center as done before with a crankcase
having a ridge.

� For opening mark, first align 360� line of degree
wheel with BOTTOM of MAG side inlet port.
Then, find 145� line on degree wheel and mark
crankcase at this point

Providing the rotary valve is the stock one not modified.

� For closing mark, first align 360� line of degree
wheel with TOP of MAG side inlet port. Then,
find 71� line on degree wheel and mark crankcase
at this point.

� Position rotary valve on shaft splines to have
edges as close as possible to marks.
NOTE: Rotary valve is asymmetrical. Therefore,
try turning it inside out then reinstall on splines to
determine best installation position.
Apply injection oil on rotary valve before closing
rotary valve cover.
 
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