[turbopete]

You may just want to be sure Curt that you don’t block the weep hole in the case between the 2 seals. Otherwise, I don’t see why they can’t be moved a bit. Never had to do it, and havn’t had one apart for a little while though.

Other option of course is to get another shaft as I am sure you have thought of. Probably too expensive, but I suppose a good machine shop could build it up and cut it down on a lathe for a new surface.


As for the outer seal, did you remark if it was flush with the cases, and if yes was there some space between it and the rubber gasket/steel plate? Just wondering if the outer one would get knocked in when you tap in the plate. Again, forgive me if I am off on something, been a few years since I put one together.

Also thinking about your spacer, it would have to be just on the outer edge right? - As to not touch the seal lip.

 

[JP700]

What do you think of my post 136?

I don't know. I only had the RV section apart once it was way too many years ago. But with only 3700 miles on the motor, I'm thinking that this could be 'normal' and not result in any problems. To your point about your 7500, RV was not new to the 521 engine.

 

[curta3531]

You may just want to be sure Curt that you don’t block the weep hole in the case between the 2 seals. Otherwise, I don’t see why they can’t be moved a bit. Never had to do it, and havn’t had one apart for a little while though.

Other option of course is to get another shaft as I am sure you have thought of. Probably too expensive, but I suppose a good machine shop could build it up and cut it down on a lathe for a new surface.


As for the outer seal, did you remark if it was flush with the cases, and if yes was there some space between it and the rubber gasket/steel plate? Just wondering if the outer one would get knocked in when you tap in the plate. Again, forgive me if I am off on something, been a few years since I put one together.

Also thinking about your spacer, it would have to be just on the outer edge right? - As to not touch the seal lip.

Hi Pete, JP,
I did take a few measurements. See the photo below. The "AS IS" configuration is the factory configuration. My plan is to add another spacer ring (outside diameter) between the bearing and the first seal. This will move both seals forward by 0.062 inch.

For the AS IS config:
weep hole is at 0.380 - 0.212 with the spacer at 0.261

For the FIX config:
weep hole is at 0.380 - 0.212 with the spacer at 0.323

It should be fine since the spacer ring is a split ring.

Time for a beer!

 

[turbopete]

It may have just been an oversight but make sure the seals go in front face to face. I am sure you took note when you took it apart.


Another thing I have done is get these seals at a bearing store as opposed to a Skidoo part, often the replacement will have the same ID/OD but usually thinner. The different thickness could let you have some change in where the seal rides on the shaft.

 

[curta3531]

It may have just been an oversight but make sure the seals go in front face to face. I am sure you took note when you took it apart.


Another thing I have done is get these seals at a bearing store as opposed to a Skidoo part, often the replacement will have the same ID/OD but usually thinner. The different thickness could let you have some change in where the seal rides on the shaft.

Both seals are installed with the seal lip (knife edge) towards the rear per my manual. Please check your later manual to see if they changed that. The idea is so that the seal spring is not in the coolant.

 

[turbopete]

Looks like they made a change at some point, not exactly sure when. I guess I have worked on newer ones, and they have both backsides to the liquid, which is what I am used to in years of automotive work.

 

[turbopete]

Looking like the change was made for 89, but was also the change from the type 537 to 536 so? Anyway 89 on shows it face to face on the 521 and 470, but there was the addition of a big rubber washer and a metal plate between the seal and the impeller - I think thats the difference - yours doesn’t. I would say go with the way it was, and as your manual says.

Wish I had the ”one day school” book for 89, I am sure it would be explained.

 

[Vmax540]

Good looking sled and a fun project !

 

[curta3531]

I bought the Winderosa gasket and seal set. Presupposing that I cannot buy standard size OEM or Weisco pistons, what brands seem to be of decent quality based on experience?

 

[turbopete]

You can get Wiseco. I have also seen Elco’s NOS on Ebay. I just received a BSL piston, really impressed with the look of it. I have not used them before but do have BSL rings in my 91 Mach on the stock pistons.

I have also used ProX that seem a step above some aftermarket and their kit included the wrist pin bearing. That being said, there are tons of SPX and SPI in sleds. A piston thread is almost like an oil thread lol.


Here is the listing for Wiseco and Pro X, only listed for 86 and up though, but assume that is what you will have to get. Wiseco, Pro X and JE are all owned by the same company. Pro X has been a big name in motorcycles for a long time.

Product Search Engine For All Products - Wiseco Piston Inc.

www.wiseco.com

 

[curta3531]

Yes, Wiseco pistons are listed for 86 and up. They do not list 1985 type 537. I know the part numbers for the 85 pistons and cylinders. I want to find out if the 86's list the same part numbers before I feel good about ordering those.

 

[dlphnfn]

Late to the party on this thread, but great work so far! Fun watching these builds come together.

 

[turbopete]

420995285 for 87, could not find 86….yet. Keep in mind for say a 583, there are several different part numbers over the years, yet all replaced by the same number in aftermarket. Also some 2 ring pistons can be replaced with single ring. 3 ring by 2 etc. Just to say it may not be exactly the same but will work fine.


My catalogue here for SPI lists the same piston 85-91.

 

[whiteghost360]

Very nice work! nice to see you take it to this level.

 

[revrnd]

Never had a recall on my '85 MX (owned it for 4 years since new) about the axle.

(Fill in the blank) are those welds awful! Did Stevie Wonder take up welding? A tip I remember from back in the day about trailing arms was to fill them with spray foam insulation if you're concerned about the strength of the Kimpex pcs. My brother had a piston break a ring on his '86 Plus & the damage looked similar.

 

[curta3531]

Thanks all. I am going to use the Wiseco pistons. I am in the process of cleaning up the damaged cylinder with a hone hoping not to have to go oversize. I am still in limits but can just barely feel one score mark. I think (with my eyes shut) I would not be able to feel it. LOL.

I'm not sure what it costs now a days to bore a cylinder oversize??

85 Plus - 521cc

Explore this photo album by Curt Anderson on Flickr!

www.flickr.com

 

[Turbomatt]

Anything new on this resto project

 

[curta3531]

Anything new on this resto project

Hi Matt. I was away in Pittsburg NH riding. The motor is going back together. I assembled the RV shaft, bearings, seals and installed them to the upper case. Lots of measurements to take because I want the lips on the three seals to not ride in the grooves made by the old seals. I spent lots of time cleaning parts. The new head came yesterday.

All -
The gasket and seal set included the PTO and MAG crank seals. The PTO side has a raised ridge around the OD of the seal to engage the case groove. It also has the legs to maintain the gap for the oil passage. The MAG side has neither of these features.

a) Yamabond the seal OD
or
b) Locktite 515 the seal OD
or
c) dry

 

[Brad460]

My vote is for Yambond 4- has never let me down.

 

[Turbomatt]

Thanks curt. I didn’t want this post to die have enjoyed following your build. Love to see these old PRS sleds being saved. My first ever ski doo brand was a 92 plus with a red windshield back then I thought I had the world by the tail only the 617 Mach was bigger then what I had in that model year. Wish I could find another one now