Crank bearing issue

[Gary pope]

Ok here’s the dilemma I have. I am in the process of rebuilding a 717 motor out of 2 different parted out motors. I notice that the good crankshaft I’ll be using has a different pro seal than the other one. One is flat while the other one is slightly rounded out. I guess my question is I need to slightly move the outside pto bearing inward a few cm is all. Can I just tap it down with a hammer and a socket or do I heed to use a bearing separator to do it?

 

[mikidymac]

The 717 uses the same crank from 1996-2004 so yours shouldn’t be different.

Can you post a picture of the issue? The PTO seals go in the case so the crank shouldn’t matter.

 

[Gary pope]

I measured the difference between the 2 outside pto bearings on both motors and one was more spaced out than the other.

 

[mikidymac]

Then something might be wrong. Seadoo uses the same part number for all the years I listed above. They shouldn’t be different at all.
I have the actual PTO distance gauge for the 717 rear bearings. This is what it needs to be.

We here love helping out Gary but with all these issues you are having with these used parts I can’t help but think these aren’t going to run for very long. The cranks just seem so questionable but we’ll keep helping.

 

[Gary pope]

I’m actually referring to the distance between the bearings is different.

 

[Chester]

I’m actually referring to the distance between the bearings is different.

They shouldn't be.

Chester

 

[Gary pope]

It is . My original question was can I just tap it down a tad bit or do I need to get a bearing separator

 

[DanSquires]

You need to lay the crank in the case and see if the pins line up with the notches. If they don't, you can adjust with a hammer. Don't go banging around on the outer bearing shell, you need to hit the inner race. I only do that with my press, but that doesn't mean it can only be done with a press.

Hit lightly, it really doesn't take a whole lot to screw up the runout.

 

[mikidymac]

I’m actually referring to the distance between the bearings is different.

I know Gary, the picture I posted is of the factory gauge that is used to set the clearance between the two bearings. You press on the inner rear bearing closest to the crank web then press on the outer PTO bearing until it touches the distance gauge then remove the gauge/spacer. So your clearance between the two rear bearings should be 0.552".

I would not go about hammering on the bearings as I have said before these cranks can easily be hit out of spec and some of these bearings that have been on there take a lot of force like a 20 ton press to get to move and when they do they pop and move quite a bit. It is very hard to get them to move just a few thousandths. To do it correctly you would need a plate to support the rear crank web or bearing depending on if you need the bearing to move in or out and a press to move it gently. In my opinion this is not a beat it with a hammer job.

The big picture is if your bearing has moved then something is wrong with it.

 

[DanSquires]

I kind of wish i'd read some previous posts by you, Gary, before having responded in the manner I did.. I'm not confident that you quite get how accurate these things have to be. I apologize.

I'll put it in this context..
When working a crank, you need wedges, press plates, spacers, truing stand (with knife edge bearings is my preference), micrometer, caliper, dial indicator (I use 4 at once), feeler gauges, a big press, lead hammer, brass hammer, cases, and whatever other tools that have been made along the way to get a crank straight. I get my runout on the PTO and MAG shaft to no more than .0005 while riding the outer crank bearings, which is (according to google) about 1/8 - 1/16 of the thickness of a human hair.
If you're not able to.. grasp that (?), please don't bang it with a hammer.

 

[mikidymac]

I kind of wish i'd read some previous posts by you, Gary, before having responded in the manner I did.. I'm not confident that you quite get how accurate these things have to be. I apologize.

I'll put it in this context..
When working a crank, you need wedges, press plates, spacers, truing stand (with knife edge bearings is my preference), micrometers (I use 4 at once), feeler gauges, a big press, lead hammer, brass hammer, cases, and whatever other tools that have been made along the way to get a crank straight. I get my runout on the PTO and MAG shaft to no more than .0005 while riding the outer crank bearings, which is (according to google) about 1/8 - 1/16 of the thickness of a human hair.
If you're not able to.. grasp that (?), please don't bang it with a hammer.

Well said, now where did I leave that dead horse and bat?

 

[Gary pope]

Ok, here’s the thing. The outer pto bearing’s tab broke off. What I’m going to do is just replace the 2 outer pto bearings is all. From what I’ve read, this should be accomplished by using a bearing separator...

 

[mikidymac]

That’s correct but you will need a shop press. The harbor freight 20ton is one of the best investments I have ever made.

You will need their bearing separator too.

You can get the correct bearings from Hfgreg here on the forum.
When you press on the new bearings heat them a little with a propane torch and put the crank in the freezer.

The final advice is to put a steel plate between the connecting rod and crank web so you are only pressing on the rear most crank web.

And yes, the beer taps make the press much more efficient.

 

[racerxxx]

Please...............READ THE MANUAL


It will tell you EXACTLY how to put the bearing on. It will tell you to put it on a steel plate. It will tell you to heat the center of the bearing. Literally put the torch flame INSIDE the bearing race where it will be on the crank. The heat will equally heat the center race (flame pointing straight down towards the plate thus equally distributing the heat) You do not need to put the crank in the freezer. Use a pair of pliers to pick up the bearing, it will slide all the way on the crankshaft WITHOUT using a press. I have done this with great success. You will need the bearing spacer that Mik talked about, it is hands down the safest most precise way to do it. You do not need a hammer to install the bearings. Remember read the manual. l'm Not saying the freezer would hurt anything, just not necessary in my eyes/experience.

 

[mikidymac]

Racerxxx knows his stuff. But I can say I tried it this summer on two 787 cranks and even with the crank in the freezer and the bearings as hot as I was comfortable I still needed the press to get them on.

I guess all bearings and cranks are different.

 

[racerxxx]

The bearings can take more than you think. I used OEM SKF bearings with the plastic/composite cage. They should literally slide right on.

 

[mikidymac]

I guess I am just a pansy when it comes to heating bearings.

 

[racerxxx]

I guess I am just a pansy when it comes to heating bearings.

Lol, no. It's sketchy for sure. My father in law helped me, his entire life revolved around machining and manufacturing equipment at his machine shop. I just have years of experience by my side. And my father used to use a hot plate with a steel plate on it to do it. Again, another machinist/mechanical genius at my disposal.

 

[Chrisx88]

I like to heat up a socket that matches diameter of inner bearing. After heated enough, set it on bearing for a few, transfers heat nice and not as sketchy as a torch to bearing.