Seized needle bearing
 

Hey'all - I had brand new upper gears installed in my xr. On second trip out, the drive seized, and upon inspection it was determined the needle bearing inside one of the three upper gears seized and has now been removed. Any idea what would be the cause of this, given the drive was newly rebuilt? Problem is that you can't buy just one of the upper gears, you have to but the entire set for 2k plus. This assumes we can't replace the bearing due to scoring caused when it seized. Many thanks.

Im being told the upper gear sets are BO from Merc. with no availability at this time,

Mother of Jesus - and that with their known failure rate... Like the corner dealer running out of smack.

You can get the bearing in the driven gear and race that's pressed on the tower. Better bearings will be caged instead of needle on needle.
If it seized, how hot did the gear get? Did it spin the race on the tower?
Seized from lack of lube?
Tower race pressed on too far covering oil hole?
Low level? Fill til it comes out breather, plug breather and continue filling until reservoir is full.
Alignment issue? Lots of measuring to do.

Call John at The Bravo Shop

I’ve purchased the bearings from IMCO and the Bravo shop, IMCO sells the SC gears( which are XR’s) individually

Thanks Jaay. That's the ticket.

I have only seen one of these bearings seize up,, that was because of very low oil level,,how do the upper & lower tower races look,, they should both be changed also.

On a new install if the packing grease was not cleaned out of the gear bearing and prelubed, it can seize!! If they are not cleaned and checked for rolling resistance they likely don't turn right away and will burn up. I have seen this a few times after a rebuild. Same with the lower vertical shaft bearing. It comes greased, but with the new grease they are using, they don't turn easily and can seize.
The stock bearings can be had, but they are a proprietary item and not readily available.
Hope that helps.

Dick

Many thanks for the info. - The lower upper driven gear is at the machine shop right now being "re-bored to specs". When the bearing seized it left raised (?) metal on the inside of the gear and the replacement gear on the latest rebuild wouldn't turn. I remain hopeful I don't have to purchase a new entire upper XR gear set. Any chance Dick that you have a decent used lower upper driven gear kicking around for purchase?? Thanks again.