blown bearing stuck to oil drain. identify?

[stainlesscycle]

so i drained my oil, and found this: see pic

part of a bearing cage, and tiny (1mm) ball bearings. razor blade for scale - nope it wasn't in the oil - water pump or power valve shaft have bearings that small? - it's the only thing i can think of that it could be... i'm gonna pull down and investigate.any hints as to what the cause is?

[stainlesscycle]

i looked at a spare set of cases i have laying here, the individual bearings that came out of drain are a lot smaller than the bearings in the case for water pump or pv governor shaft...


could be the inner clutch cover bearing that the pv shaft rides on... i don't have a spare inner clutch cover to look and see.. but the pv shaft is 8mm, so the o.d. of the bearing has to be bigger than 10mm..

[stainlesscycle]

clue #2?

[stainlesscycle]

ok. i've removed clutch, inner clutch cover, waterpump etc. everything looks fine inside.

aside from the broken waterpump impellor. and of course the bearing pieces stuck to the oil drain.


all bearings look good. where the heck did the broken bearing come from???

[blitz11]

Bearing fairy?


The only think i can think of is powervalve...but 10 mm OD is really small.

I just looked through the parts fische, and can't find a 10 mm OD ball bearing.

I have no idea.

[stainlesscycle]

Originally Posted by blitz11

Bearing fairy?


The only think i can think of is powervalve...but 10 mm OD is really small.

I just looked through the parts fische, and can't find a 10 mm OD ball bearing.

I have no idea.

you and me both.

the split wp impeller may be a problem in and of itself - and should have nothing to do with the bearing in the oil. testament to the need for aluminum impellers. thankfully i have one i can rob off another motor.

i am tempted to flush the crankcase, button this motor back up and call it fixed. what is the smallest bearing inside the motor? i would assume it's the impeller or pv shaft bearings, and they've gotta be close to 20mm o.d. and the loose balls in the cage gotta be 2 or 3mm at least.

i don't even know how a bearing like that could have gotten into the oil. goes to show, you gotta tear stuff down when you buy it used, to investigate.

bike was running fine - i just raced it for 2:30 on sunday, and it never had a problem - no funny noises, no overheating (70 degrees out). nothing out of the ordinary.. i'm assuming the impeller still spun, just not well.



if anyone has any idea of where the bearing could have come from, aside from sabotage let me know!

[blitz11]

Could someone have punked you? Previous owner stuck a bearing down the filler hole, dropped it in during a rebuild?

Man. That is weird. I really have no idea.

[stainlesscycle]

maybe. but when i pulled the clutch hub nut, the lockwasher was factory new. never been off. don't know where you'd stick the bearing in the crankcase...i don't think it would fit in the oil filler hole. maybe it would. rebuild would mean split cases, or at least clutch pulled. it looks like neither has been done - unless a new lockwasher was used.

[Jakobi]

Kids haven't been playing in the workshop?? Any chance it could have been in the pan prior to dropping the oil?

[stainlesscycle]

it was attached to the oil drain plug when i pulled it - it was covered in oil sludge. it was definitely in the motor.