Gear box overhaul

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Mofosheee

Mofosheee

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While in the process of overhauling my 850 gearbox; sn 306XXX, the "sleeve gear bearing" dropped out of the gearbox shell.
Examination of the seat of the gearbox shell showed that the bearing seat had been upset (with a center punch) around it's entire circumference. Probably to secure the bearing in the shell to prevent rotation.
Was this a factory practice or someone's fix? Should I re-center punch the surface? Any bearing and sleeve retainer compound recommendations appreciated.
Thanks
 
Never have seen it as a factory procedure. You might have a machine shop pin the bearing. But one wonders
if the gearbox shell isn't knackered at this point.
Loctite makes stud and bearing sealants.
 
Mofosheee said:
While in the process of overhauling my 850 gearbox; sn 306XXX, the "sleeve gear bearing" dropped out of the gearbox shell.
Examination of the seat of the gearbox shell showed that the bearing seat had been upset (with a center punch) around it's entire circumference. Probably to secure the bearing in the shell to prevent rotation.
Was this a factory practice or someone's fix? Should I re-center punch the surface? Any bearing and sleeve retainer compound recommendations appreciated.
Thanks
Click to expand...
Shouldn't fall out without punching (never seen a punched one). Usually requires heat to get them out. Locktite for bearings might work, but it sounds like the shell is bad to me.
 
Check for a crack between the two bearing bores, if it has been bodged to that state (centre punching).
Surely it is not punched in the bored area of the bearing OD ?
 
No cracks by die penetrant
It is punched PRECIOUSLY in the bored bearing OD. :(
I'm not liking this
Thanks again Time
 
It would probably need precise ID measuring of both bores to see what dimension you have and their roundness (compared to new bearing OD's)
Maybe even Loctite 660 is an option (on a keeper bike)
The problem with buying a used replacement case is they are still an unknown (compared to an expensive new case)
 
centre popping the parent bore is a practice used for many years, It does work depending on the extent that the wear to the parent bore, but from my experience even when using a bearing lock & centre popping its only a temp fix
 
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olympus said:
centre popping the parent bore is a practice used for many years, It does work depending on the extent that the wear to the parent bore, but from my experience event when using a nearing lock & centre popping its only a temp fix
Click to expand...
Agree it's a temp fix . Seen it on other applications. Old brits article referrenced this very issue; No indications that the bearing spun in gear box case.
Thanks to all
 
The same had been done in my box, but not all the way around, maybe 6-7 punches in the housing on both bearings on the DS and that had been done with the bearings in place. I don´t quite see the point with this, can somebody really believe that you can squeeze the bearing tight, it is pretty damn hard compared to the aluminium in the housing, by a few punches? Well I don´t believe that works so I got hold of a very good GB shell from the US, an early one from late -69 in perfect cond. When I placed the new bearings in I glued them both, so now I hope they stay in place.....
 
I'm not feeling lucky, looks like new case; new to imgur..........hope image posts
 
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Never seen any shell or bore where someone has done that . When someone decides to center punch it's usually after the bearing is home in it's bore and the softer aluminum gets a few punches to press it tight to the bearing outer , to prevent any spinning or drifting of said bearing. The Locktite 609X looks like a viable option at the moment.
 
That's also known as putting a raspberry on it. Either buy a new shell or loctite new bearing. Based on the fact that your bearing fell out without heating the shell, go for a new shell. You want to put it all back together and not think about going back in for a long time.
 
Deckard said:
That's also known as putting a raspberry on it. Either buy a new shell or loctite new bearing. Based on the fact that your bearing fell out without heating the shell, go for a new shell. You want to put it all back together and not think about going back in for a long time.
Click to expand...
Agree, I hate doing things twice.
 
In the non PC world of NZ engineering workshops that is known as Chinese writing.


And it's a bodge. The fact the bearing fell out shows it doesn't work.

I had to buy a new Andover Norton case for my gearbox. Works well.
 
273.91 sterling about 375 USD plus PP and taxes I dunno 425-450ish?
Brand new. Probably worth it.
 
I have heard of electroplating the OD of a bearing for a better interference fit. Is that a real option??
 
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