HELP! Ball bearing on my drain plug!

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#1
Help!

I just changed the oil in my 2005 YZ125 and I found about 7 or 8 tiny (much smaller than a BB) ball bearings on the magnetic drain plug. There were also some metel fragments that sort of looked like some kind of case that might of held the balls in place. My question is what bearing is it? What could be that small in my bottom end? All the bearings in the tranny are needle bearings. (I think).

The local shop said it could be water pump bearing or power valve, but how could that be in my oil.

I trail ride the bike, it has less than 100 hours, and I only started riding in 03 so I'm about half a sqid.
 
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#2
You probably shouldn't take it to the local shop! It had to come from the transmission but I have no idea where. I'd just pull it apart and find out which bearing it was, and if it caused any other damage, or if other damage caused it to fail. You can probably look thru your manual and figure out what bearing it was, but it has to come apart anyways.

Marc -
 

mtk

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#3
The short answer is that it IS a problem and won't fix itself so you might as well start disassembling things until you find the problem bearing. Given where you found the remains, I see a bottom end rebuild in your future....
 
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#4
Funny thing. I was over at halfthrottle's house and misplaced a cup of really small ball bearings when I was changing his oil.

Nah, not funny. I had the shift drum locater dowels fall off the shift drum and go around in the oil in an old YZ 250. One showed up on the drain plug after I heard a ticking sound. When I pulled the engine apart, the little dowels had gotten between the crank output gear and the clutch boss and bent/chipped/destroyed both. hardened small objects cause gear chipping and immense forces on the gear faces and shaft bearings as they go around. Dont even roll it over. Just get it broken down.
 
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#5
My DR is down now. Bike ran fine when I put it away, pulled it out the other day and it wouldn't start. No spark. Started checking, one of the stator coils came up bad. Sure enough, there's a tooth from a gear stuck to the magnet on the inside of the flywheel. It ripped right thru the coil leaving an 1/8" deep gash thru the wire. I just parked it for now.

With metal floating around, the worst thing that can happen is it gets caught between 2 gears. Besides possibly breaking the gears, often the shaft gets bent and worse, the case gets broken.
 
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#6
In the YZ's there is bearings for the powervalve at least on my bike there is anyways. One bearing on the cover and one bearing on the case. Each has fairly small bearings. Pop your whole clutch cover side off and take a look and see what you find.
 
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#8
Sorry Half, I'm the idiot, not your shop. I don't know where my head was at but it was dark and stinky! It could be the waterpump bearing but I simply can't see it being that small. As KX pointed out, there are bearings related to the power valve, but again the balls you found are awful small. My guess would be the clutch "throw-out" bearing, but I am an idiot so keep that in mind! Just in case, check that before yanking the entire cover.
 
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#9
Hello?

If hes talking about the 2005 YZ he owns, than there is no powervalve ball bearings and if there were, there would still be no way for them to get into the crank case unless the piston was busted. The powervalve assembly is not on the side of the engine anymore.

Start looking at the exploded diagrams for the engine and planning on how to systematiclly get it broken down, starting with the easiest first which is cover removal and inspection.

No bearing ferry is going to come along and fix this for you and Yamaha doesnt make engines with extra ball bearings that arent needed.
 
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#10
BEARING (608M4ML01) UR NMB


Oh yeah, you may want to go to the yamaha parts counter and ask to take a look at the bearing listed above. If it has the same size balls as the ones you found in the case, it is the water pump shaft bearing that failed. That bearing supports the drive gear and water pump shaft and the good news would be that you only have to remove the case cover (not split the case halves) to relace the bearing! Thats easy.

Sorry if I come across pushy sounding but you need to take this seriously.

Good Luck!
 
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#12
kx125412 said:
In the YZ's there is bearings for the powervalve at least on my bike there is anyways. One bearing on the cover and one bearing on the case. Each has fairly small bearings. Pop your whole clutch cover side off and take a look and see what you find.

on my 98 yz250 the PV bearing came apart and left tiny ball bearing on the drain plug
 
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#13
NWDirt said:
...If hes talking about the 2005 YZ he owns, than there is no powervalve ball bearings and if there were, there would still be no way for them to get into the crank case unless the piston was busted. The powervalve assembly is not on the side of the engine anymore...
Umm, your head's in the same place mine was. Calling them "power valve" bearings is misleading though, they're actually the power valve governor bearings, of which there's 2 and they are contained in the crankcase. Just looking at the fiche it's hard to get an idea of size, but balls smaller than a BB seems too small even for those bearings. That's why I suggest he checks the clutch pusher bearing first before pulling the entire r/s cover.
 
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#14
i had the same problem and it did all sorts of damage. the bearing that exploded is the shift stopper lever. yamaha knows about this problem and they have updated the part to a solid roller. hope this helps
 
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#15
Psylo535 that would be why the parts fiche does not match his bearing!I knew that size of a bearing did not jive with any of the ideas,they are all bigger than a bb!Halfthrottle you will need to account for every bearing,pieces of races or surely split the cases to MAKE SURE there are none left in your engine.If the damage was contained to the bearing I would consider betting on a longshot in vegas!