720 rear rotary shaft bearing seal or not?

[Mekanix]

Just assembling my top case half and I've noticed a bit of a problem

1. the old bearing didn't have a seal on the back side of the inner bearing of the rotary shaft. You know, the one that stay's in the case.

Also there was some fluid back there that was a different color than what was in the rotary bath. ( looked like synthetic xps)

2. The new bearing I have is sealed on both sides.


Should I remove the outer seal and fill the cavity with some sort of oil ? 30w ?

or should I just asemble it the way it is with both seals in tact and leave the cavity empty ?

It is a sealed cavity...


Thanks

 

[racerxxx]

That is correct, the one side does not have a shield--the open side goes towards the outside of the case. When I do them I press the bearing in then add oil through the bore of the bearing--XPS-II or what ever 2 stroke oil you're going to use. If you take the bearing and suspend it (shield down) and fill it with oil on the open side you will see it drain out slowly, it's not sealed it's shielded to keep debris out. So the oil from the RV cavity will lube the bearing, it does not get a separate type of oil. The bearing is a SKF 6201-Z the single Z designates a single metal shield, a -2Z would be a double metal shield. I just bought an OEM BRP (SKF) for $11 shipped still in the bag off Ebay, $3 plus tax cheaper than the dealer. I would not mod a bearing that has both shields, god for bid one thing goes wrong you're back into that case again. Also if it is rubber sealed (6201-RS or 6201-2RS) I would not use it, those are permanently lubed bearings. Any bearing or seal inside the engine I will not compromise on

 

[Mekanix]

It is the 6201-2RS. This is why I asked
I didnt realise that it was a sheild and not a seal on the original.

Might as well get the right one.

Thanks racer

 

[racerxxx]

It is the 6201-2RS. This is why I asked
I didnt realise that it was a sheild and not a seal on the original.

Might as well get the right one.

Thanks racer

No worries Mek. I actually just ordered the one at the other end (6203TN9/C3) from the dealer, it's plastic/fiber caged. My local supply house was more for it and a long delivery, the dealer is a 3 day delivery for me.

 

[Mekanix]

Cool. The dealer here has one for $15 so I went for it.

 

[racerxxx]

That's not bad at all, no work stoppage either while waiting for parts.

 

[Mekanix]

Yeah. Waited long enough

Is the rotary valve gear supposed ro be centered or is it supposed to be more towards the rotary valve side.
Mine is slightly towards the rotary valve side and I can see the wear pattern on the gear is not centered when I moxked everything up.
But I think while running, the gear should center itself under load.
what do you think?

 

[racerxxx]

Do you mean the brass drive gear on the rotary shaft?

 

[Mekanix]

Yeah. The shaft is assembled correctly and the bearings are seated all the way in the case but if I look down fron the pto side, the gear is not perfectly centered in the center of the crank gear.

 

[racerxxx]

Your lucky day, just happen to have a 720 split in half.

Sent from my SGH-T889 using Tapatalk

 

[Mekanix]

Awesone.
Heres mine:

 

[Mekanix]

They do look the same

 

[racerxxx]

 

[Mekanix]

Lol yuuuup.

Back to the build. Thanks again!

 

[PGHMAN]

Any tips to install the rv shaft back into the case? I pulled the shaft yesterday on the 720 and plan to replace the bearings and seal...once I figure a way to press off the bearing off since I don't have a press. Any thoughts?
Thanks.

 

[Mekanix]

Make double sure the shaft isn't bent.
The rear bearing is not sealed, it's just guarded and allows oil to pass through it.

Bearing on the shaft comes off with heat from a heat gun.
A good puller does help and can be used for crank bearings.
Buy a press it comes in handy for lots of repairs.

 

[racerxxx]

To do it the right way you will need an internal bearing puller or a blind hole bearing puller. Harbor Freight has one pretty cheap . To remove the bearing from the shaft you will need to remove the little c clips on the shaft then everything will slide off except the bearing. For that you can just open a bench vise wide enough to clear the splined end and let the seal and bearing rest on the top of the jaws. The with a rubber or plastic mallet drive the shaft towards the ground. Put a box under the vise to catch the shaft so it doesn't hit the floor. Then grease the shaft and slide the seal on, then put the bearing on. I think I used the metal spacer from the assembly and a socket to clear the splines on the shaft but allow you to drive on the center race of the bearing. Do not drive on the outer race of the bearing you'll ruin it. Once that is on you can slide it all back together and put the c clips on. Remember to layout the shaft as you disassemble it so you have the order correct. I think a deep 13/16 craftsman socket and extension is what I used to drive the inner bearing into the case, put some 2 stroke oil in the bearing center before you put the shaft back in the case. The worst part of the entire job is putting the shaft back in, you need to drive it all back in. I think I used the rotary gear to get it started, then you need to pay attention to the seal and drive that in while you move along. Use a socket that will catch the outer edge of that so you don't dent or fold the seal in. See, it's easy! Actually if you just take your time and use your head it's not that bad of a job at all. Don't forget to put the big snap ring back on before you walk away and forget to do it.

Wow, Thought I paid like a 1/4 of that, find a coupon.

http://www.harborfreight.com/blind-hole-bearing-puller-95987.html


Here you can see in my 95 thread

http://www.seadooforum.com/showthre...ugar-and-Spice&p=408997&viewfull=1#post408997

Installation of shaft

http://www.seadooforum.com/showthre...ugar-and-Spice&p=426869&viewfull=1#post426869


Layout the assembly

 

[Mekanix]

What he said :agree:

 

[racerxxx]

Make double sure the shaft isn't bent.
The rear bearing is not sealed, it's just guarded and allows oil to pass through it.

Bearing on the shaft comes off with heat from a heat gun.
A good puller does help and can be used for crank bearings.
Buy a press it comes in handy for lots of repairs.

Not that it's wrong but I have never used heat on anything other than restoring plastics on a Seadoo. The bearings are a press fit, but not overly tight.

 

[racerxxx]

Double post

 

[PGHMAN]

Many thanks Dan for the quick and thorough response. Look's to be pretty straight forward.

 

[PGHMAN]

Make double sure the shaft isn't bent.
The rear bearing is not sealed, it's just guarded and allows oil to pass through it.

Bearing on the shaft comes off with heat from a heat gun.
A good puller does help and can be used for crank bearings.
Buy a press it comes in handy for lots of repairs.

I would love to have a press and may consider at some point. Did you replace the bearings or just the seal?

 

[Mekanix]

Not that it's wrong but I have never used heat on anything other than restoring plastics on a Seadoo. The bearings are a press fit, but not overly tight.

I usually use low heat which is why I use a variable heat gun. About 350-400 F which is well below what it would take to do any damage but it does make the bearing slide on easier. I wouldn't use a torch though.

 

[Mekanix]

I would love to have a press and may consider at some point. Did you replace the bearings or just the seal?

I replaced both bearings and the seal and the shaft. Someone else installed the bearing and seal with a press before I got it. All I did was install the rest after that and the case bearing.

I did play with the bent shaft just to learn from it. The Bearing was stuck on there but after warming it up I could tap it and the seal off with little effort. I tried taking it of and re-installing it a few times just to see what it took and to make some tools out of pipe just the right size for the next time.

 

[PGHMAN]

I usually use low heat which is why I use a variable heat gun. About 350-400 F which is well below what it would take to do any damage but it does make the bearing slide on easier. I wouldn't use a torch though.

So you heat the bearing prior to install? Same for removal? Any idea where pick-up bearings? I have a new seal.