Rear Crank Seal lose

D

Daddydune

Location
California
So starting a 701 rebuild for a 1991 Superjet, got parts, painted cases, cleaned everything. Existing crank look good, bearings spin free, no noise, no movement, great. Test fit new seals and run through installing crank in case so I know what to see and feel before my final install with sealant.
Put new seal on front of crank and great fit. put on rear of crank and they are lose on the shaft. They don't fit tight on the shaft. I have never put one of these together so I thought I had the wrong seals or something.
Have another crank that has bad rod bearings so I try the seals on it and they fit nice and no slop. Mic the crank seal surface and compare to my good crank and my good crank (the one I want to use) is .066 smaller dia than the bad crank.
Is it normal for the seal area to get smaller? Do they make oversize seals for this? Do they make a sleeve for the seal surface?
Do I get a new crank?
Lucky me it looks like I have two bad cranks.
Thanks for any knowledge on this seal issue.
 
Wizards Powersports

Wizards Powersports

Location
Denver, NC
Sounds like the crank you are trying to use may have had a sleeve on it at some point. SBT sleeves the seal area when it is corroded or damaged - not sure how much (if any) material they remove, but that's my best guess. The sleeve they install can slide off and be lost once they coupler is removed...
 
Quinc

Quinc

Buy a Superjet
Location
California
Wizards Powersports said:
Sounds like the crank you are trying to use may have had a sleeve on it at some point. SBT sleeves the seal area when it is corroded or damaged - not sure how much (if any) material they remove, but that's my best guess. The sleeve they install can slide off and be lost once they coupler is removed...
Click to expand...

Learn something new everyday!
 
D

Daddydune

Location
California
Update, Check Yamaha and the 6m6 sleeves are not available but I did find out today there is a 62T sleeve. When I called SBT and spoke with them and they have a replacement sleeve. It was $18. Got one and it's OD fit the new OEM seals perfect. But it does not slip over the crank so I thought the existing sleeve was just worn. That's crazy now that I think about it because it's not worn in one place like where the seals ride, it's very flat and smooth across the whole surface like it's the wrong collar. (Hint, the collar is missing?)
So talked to a couple of people who said just weld something on the sleeve and pull it off. So I welded couple of nuts on there and it does not budge, nothing. I cut a grove in the collar or what I thought was the collar to relieve the collar. Still no move! I managed to bend the puller bolts and pulled the welded nut off, not much of a welder I guess.
I checked the marking on the crankshaft and it is a 6m6, so I have the correct collar. I'll revisit it in a few days and see, maybe I'll take it to a shop.
Hope I have not just wasted my crankshaft.
 
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