Thread: SL750 Rear Motor Seal
01-18-2007, 04:20 PM #1
SL750 Rear Motor Seal
This is the seal that I pried out of the rear of my 95 SL750:
As you can see, it does have a lip! So it was extremely difficult to get out. The new, replacement seal from Partsland didn't have this lip.
I put in the replacement seal in, and did a leakdown test, and it's tight. (The rear seal was tight, the front crank seal is another story! Damn...)
Can anyone explain why the rear seal in my motor wasn't the correct one? The motor was supposedly a virgin, and low hours. It looks it, too, beautiful condition.
01-18-2007, 04:38 PM #2
The inner seal on the PTO has a lip the outer PTO seal does not. Mabe who ever assembled the motor last got them backwards.
Quote from the Polaris service manual
Note:The metal sides of the PTO end seals face each other. The innermost seal has an outer rib to fit into the groove in the crankcase. The spring on the Magneto end seal faces inward toward the crankshaft.
01-18-2007, 04:54 PM #3
Yeah, that's kinda what I figured, that the inner and outer seals have been reversed. But the cases aren't dripping with Yamabond or anything, so I'm guessing this was done at the factory?
Do you think it's anything to worry about? It passed the leakdown test to 9psi, no leaks whatsoever in the rear.
I used a regulator to hold the cases at 9psi, sprayed Windex and looked for leaks. When I shut the air off, the pressure dropped fairly quickly to 5psi, then slowly continued down to 2psi. Dropped from 5 to 4 psi over 40 sec, from a slow leak on the front crank seal. I understand a good leakdown test is 5 to 4 psi over a period of 1 min or more, so I'm debating whether or not to split the cases over this.
01-18-2007, 05:11 PM #4
Your this far into it and do not want to pull the motor when it is done. I would filp it over pull the 21 bolts and remove the bottom case and have a look. Then replace the front (mag) seal. and make sure the inner PTO seal is correct. It is much easer to do now than wait untill there is a problem.
01-18-2007, 05:36 PM #5
Ok, I don't have to pull cyl's, pistons, etc? Just flip it and pull the bottom off? Can the seals all be changed in this manner as well? Without pulling the top end apart first? Because if I can open it up in that manner, I will, and just order the seals, install them and be done.
The whole reason I bought this motor was because it was cheaper than rebuilding my 650 and converting it into a 750, as well as a lot less work.
01-18-2007, 06:01 PM #6
I dont see why not you have to lift the crank up to get the seals out but only a little. Call Jay or Tony at http://atlanticpowersports.com/Default.asp
They should have the seals in stock and you get a discount if you are from greenhulk. They also have online fiche with prices.
01-18-2007, 09:18 PM #7
Ok Beerdart, that's what I'll do! Seals are already on order. I looked on the microfiche and they don't show a gasket between the case halves, is that correct? Just Yamabond or something like that?
Thanks for the sound advice!
01-18-2007, 09:27 PM #8
No gasket. 3 Bond 1215 is prefered Atlantic should have it. I use Permatex aviation form a gasket (but thats just me) Yamabond is ok if you want to cross party lines. LOL.
Rest easy peace of mind.
Last edited by ph2ocraft; 01-18-2007 at 11:31 PM.
01-18-2007, 11:26 PM #9
- Join Date
- Aug 2006
- Pittsfield, MA
01-19-2007, 09:57 AM #10
yes, just flip the motor over, and reove the bottom case 1/2. clean it up real good, replace seals, and use sealer to put it back together.
if it is not to late, i can get you seals much cheaper.
if you have them coming, i will split the cost of them with you. ( i feel bad, i know you wanted to just plug & play ).
yes, as far as i know, and by the looks of this machine, that motor was a virgin. ( i know i never pulled it here at my shop).
the other thing i wounder is....
i know on some of the kawi motors, the front seal will leak, if the stator coil assy is not installed. does anyone know if polaris is like this?
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