Rotary Valve

[jmartin915]

My ski start due to bad timing a mechanic told me. He said it was possibly the rotary valve gears. I'm one my way there and have the bottom end off and moved the pistons up and down while watching the brass gear in there and it does not appear to have any damage. Is there any reason why I would need to pull it out? Would a magneto gen. coil be the cause of bad timing??? Also, does anyone know if I "have to have" a special puller to pull the rotary valve out?

 

[seadoosnipe]

.........Wow...!

Wow, I've heard it all now.

If you split the casing and saw the brass gear wasn't damaged and there are no shavings in the casing, then the worm gear is fine. Put it back together.

If you removed the rotary valve (plate) and didn't put it back on properly, this is the only way it can be out of time. Every thing else in timing is not adjustable. If your trigger coil is on correctly (no adjustments either), your rotary valve has been set according to specs, then, your in time.........

Depending on what problems your experiencing, you may have bad rotary cover clearance. You can check this with a feeler gage. I'd have to go in and get the measurements, but I know, that if the cover is to close to the valve, it may cause over heating, to far away, backfiring and hard starting. Or vice-versa. You'd have to get a machine shop to either build it up and turn it down, or buy another cover............:cheers:

 

[timmyboy76]

when put'n back together, the RV setting is 147*, or if you wanna double check...

 

[seadoosnipe]

Rotary valve.......

The rotary valve for the 717 is part number 290-924-502 and is a 159* valve. I think what timmyboy is saying is, to check the timing, you have two marks to make, with a degree wheel, you have to set the first mark at 147* +/- 5* to set opening BTDC and to set close, you'll have to mark 65.5* +/- 5* for closing ATDC......
It's not a hard procedure.......I'm sure if you use our search engine on the tool bar, keyword, rotary timing.......you should come up with the procedure.:cheers: