Timing 1994 657X Rotary Valve

[MontanaXP]

I am having trouble finding some instruction as to how to re-install my rotary valve on my...

1994 SeaDoo XP
657X Rotax

If someone could point me in the right direction it would be much appreciated.

Also some of you may remember me from last summer, I had the starter gear dislodge from my flywheel and bind on the motor housing. I have since had that gear pressed back on since I was unable to get a replacement flywheel/mag assembly. Is it okay to tack-weld that gear from the backside to prevent it from dislodging again in the future or am I risking damaging the magnets of the flywheel?

Looking forward to getting this baby running again!

 

[shakedown]

timing

I wouldnt try welding it, it may demagnetize your flywheel. as far as the timing you need a TDC gauge (top dead center gauge) & a degree wheel as well as a shop manual. I did mine with a straw and I found a printable degree wheel. but you still need the instruction page from the manual. I think there is a degree wheel on this site somewhere. Here it is....

http://www.seadooforum.com/showthread.php?t=12763&highlight=degree+wheel

 

[seadoosnipe]

Welding?

Yeah, I remember you from last year, not because of the name, because of the crazy avatar. That looks like something I'd do while working on an engine. You look like your looking really hard for that last BEER!....:rofl:

I don't hold a degree in electrical engineering so I might be wrong on this. I believe if you were to tack weld this ring gear back on, you'd have to TIG it. When you weld, the arc will follow the electrical current from the tip to the ground. If the welder were to place the ground close to the area of the tack, then the flow of electricity will be from point A to point B. Now, if he were to weld at say the 12 o'clock position and have the ground at the 6 o'clock position, I can see where there might be some interference to the magnets, since the field of current would possibly be crossing over them. But, I saw a show on the "Discovery" channel (yeah, my fav!) called "how things are made" and they made a magnet. From what I saw, if you did by chance de-magnetize them, you could use another magnet to rub over them to re-charge them.

But, I'd ask the welder. He's probably have the best answer.:cheers:

 

[MontanaXP]

Ah yes I will never forget THAT day at the lake, it was about 50 degrees out and the gear for my trim motor cracked in half :hurray:

You could safely assume that current from a welder would flow from point A to point B. I may try clamping the ground on the starter gear at the point of the weld.

I have never had to make a magnet but I did stay at a Holiday Inn Express last night


Ah yes... I do have a degree wheel and the cylinder head(s) is pulled off. I have read the thread for someone's 1993 657 motor but I am guessing that procedure will be different for my 1994 657X motor. Can anyone post the short and sweet on which degrees to mark etc?

 

[seadoosnipe]

No probs.....

For that year, they made two different degree wheels. The XP used the 159* all the others used the 147*, so make sure you have the correct wheel.

If you've read the thread on how to do it, then you only need the opening and closing, which is 149* open and 65* closing. That'll be +/- 5. Also, remember, if the wheel doesn't match exactly, try and turn it over. They ar not designed asymetrical. :cheers:

 

[MontanaXP]

For that year, they made two different degree wheels. The XP used the 159* all the others used the 147*, so make sure you have the correct wheel.

If you've read the thread on how to do it, then you only need the opening and closing, which is 149* open and 65* closing. That'll be +/- 5. Also, remember, if the wheel doesn't match exactly, try and turn it over. They ar not designed asymetrical. :cheers:

Thank you! Yeah the 657X has the oval openings and the 159 degree valve. And yep, 149 and 65 are what I used and indeed I did have to flip it over, and now IT RUNS! Well it ran...tried to restart it and the starter sounds like it's toast

The local boat dealership let me photocopy their shop manual, you're right those pictures are worth a thousand words!

Now, if I could just find a starter... :hurray:

 

[MontanaXP]

I suppose since I found my answer I could post it here in case someone else searches in the future.

This is for a 657X (has oval openings instead of round ones)

Place degree wheel over rotary gear and align the 360 degree line with the bottom of the MAG intake. Follow the wheel counter-clockwise and make a mark on the casing at the 149 degree mark (211 degrees clockwise).

Align degree disc 360 degree line with the top of the MAG port. Follow the degrees clockwise to 65 degrees and make a mark on the casing. Remove degree disc.

Bring the MAG piston to the highest point, TDC (Top Dead Center). You can use a tool made for measuring this point or you can flip over a spark plug and eyeball it. I had my head pulled so I eyeballed/felt it.

Place the rotary valve over the splines with each edge lining up with the marks you made on the casing. If you can't get it exact try flipping the valve over and placing it on again. You should be able to get it pretty close. Your allowable margin of error is + or - 5 degrees.

Enjoy!