How Far Can A Bearing Go?

[Bob Hedgecutter]

So a guy dropped off an interesting saw he was having problems with, hard starting, intermittent running, wont hold tune......
Perhaps more interesting was the fact it is a short case with a poly flywheel.

Long story short- lots of clutch side crank play, but needle bearing in clutch bell was fine.
Tore it down, pulled the crank- clutch side bearing stayed together until I removed the oil seal from the bearing after splitting the cases.
Don't think I have seen one this bad without catastrophic failure before- must have been close to "BANG".
Has been real hot, bluing and burring to inner face, cage hard and brittle- some of it missing and balls could shift within the race.

 

[grizz55chev]

Nice save! I had a 435 Husky that had completely worn out the seal on the clutch side, wouldn't hold a tune, bearing was not visibly worn. Replaced both along with the rings, runs like new!

 

[Bob Hedgecutter]

Nice save! I had a 435 Husky that had completely worn out the seal on the clutch side, wouldn't hold a tune, bearing was not visibly worn. Replaced both along with the rings, runs like new!

Save? Jury out on that one.
The guy had not long bought it- online and paid too much for it. Old 066's command a good price here, even ones well worn after a pro logging life.
My guess is, previous owner did enough to get it running, maybe built it up out of scrap parts, but did not split the cases and do the bottom end. Has a fairly new aftermarket piston in a decomp cylinder that shows plenty of wear- short case, poly flywheel, aftermarket recoil......
New piston is scored and the rings are pretty rough after only a couple of tanks by the new owner- bad oil seals can do that.
I think I have enough parts to make it good again, so can probably rebuild it cheap enough, but it still won't be free and as I say- it already cost him a bundle.

 

[Mad Professor]

Were the cracks in the race there before you split the case? Surprised it didn't grenade the bearing and/or spin the outer bearing race.

Does the bearing seat in the case look O.K.?

 

[Bob Hedgecutter]

Were the cracks in the race there before you split the case? Surprised it didn't grenade the bearing and/or spin the outer bearing race.

Does the bearing seat in the case look O.K.?

Yes, cracks were evident before removal. This (or past bearings) have spun by the looks, pocket is a little scuffed and some track marks on bearing outer race, but the major crack this time effectively locked the outer race in place.
It will never be perfect again but might knit up with fresh bearings and seals to be a homeowner low use saw again. Or I check my stash to see if I have anything better and just start fresh.

 

[L34]

Also have a shortcase/poly wheel Bob.

 

[grizz55chev]

Save? Jury out on that one.
The guy had not long bought it- online and paid too much for it. Old 066's command a good price here, even ones well worn after a pro logging life.
My guess is, previous owner did enough to get it running, maybe built it up out of scrap parts, but did not split the cases and do the bottom end. Has a fairly new aftermarket piston in a decomp cylinder that shows plenty of wear- short case, poly flywheel, aftermarket recoil......
New piston is scored and the rings are pretty rough after only a couple of tanks by the new owner- bad oil seals can do that.
I think I have enough parts to make it good again, so can probably rebuild it cheap enough, but it still won't be free and as I say- it already cost him a bundle.

It has at least a 50-50 shot at being a decent runner again, much better odds than if the bearing let go.

 

[Bob Hedgecutter]

It has at least a 50-50 shot at being a decent runner again, much better odds than if the bearing let go.

True that. But the owner is not in a happy place at the moment- I keep telling him about things I keep finding that need fixed and the seller does not want to know about it- not admitting any fault, but not denying it either! He certainly will not refund any $ though. Might be cheaper to sell the poor guy a spare 066 I have here.

 

[cookies]

high temp red locktite the new bearings into the case?

 

[Bob Hedgecutter]

Also have a shortcase/poly wheel Bob.

WAY nicer than what I am playing with- but it looks overly white- has it been repainted or repowder coated?
Or do Aussie saws just not get used much!

 

[Bob Hedgecutter]

high temp red locktite the new bearings into the case?

Not sure if it will be needed- if the saw gets rebuilt on these case halves.
I pulled a crank into that case half with a 6203 bearing and it is snug as a bug in a rug. (Don't have any of the proper bearing in stock as they are dear as poison over here!)

 

[Bob Hedgecutter]

Not that it means much- but this bearing was a FAG made in Portugal, the usual Stihl specific clutch side bearings in saws here are NTN made in Taiwan.

 

[L34]

WAY nicer than what I am playing with- but it looks overly white- has it been repainted or repowder coated?
Or do Aussie saws just not get used much!

Yes Bob repainted.
Had local auto shop mix paint to Stihl color.
It does look bright in the pic but it is ok in real life.
Yer only cut about 6 rounds since rebuild lol.

 

[drf255]

That’s a good one Bob.

I had a 460 here recently with a bad flywheel SKF I actually installed myself. It went in around 20 tanks.

The bearing was so worn that the inner race could be pushed out around .125 from the outer.

 

[Bob Hedgecutter]

That’s a good one Bob.

I had a 460 here recently with a bad flywheel SKF I actually installed myself. It went in around 20 tanks.

The bearing was so worn that the inner race could be pushed out around .125 from the outer.

I took the remains of that bearing into the local Stihl agents today to order a new set of bearings and gasket set. The owner said "really! In 25 years I have never seen one that bad!"

 

[Huskybill]

Bearing problems that’s either lack of lube or an air leak?.. what u say? Unless it’s high usage and old age.

I cringe when I see many using 50:1 ratio.

With dirtbike two strokes I got into the habit of doing crank bearings, crank seals, check the crank rod bearing for excessive play, assemble the engine and leak down test it. Then I know it’s good, no different with saws.

 

[Bob Hedgecutter]

Bearing problems that’s either lack of lube or an air leak?.. what u say? Unless it’s high usage and old age.

I cringe when I see many using 50:1 ratio.

With dirtbike two strokes I got into the habit of doing crank bearings, crank seals, check the crank rod bearing for excessive play, assemble the engine and leak down test it. Then I know it’s good, no different with saws.

No real idea Bill.
Seeing as how it was never my saw, but I can tell it has been hot, can tell you the seal was fried and I cannot really understand how the saw ran enough to do that to the bearing!
Maybe a previous owner was able to tune it rich enough that it only required a daily change of piston and rings?

 

[Huskybill]

My son is running my 365 and 570 saws I told him to add a tad more husky oil to the 50:1 pre mix husky cans of fuel. I can’t accept the 50:1 ratio yet. I ran the older husky saws on a tad richer than 40-1 they required for many years I ran around 38-1.

 

[Bob Hedgecutter]

My son is running my 365 and 570 saws I told him to add a tad more husky oil to the 50:1 pre mix husky cans of fuel. I can’t accept the 50:1 ratio yet. I ran the older husky saws on a tad richer than 40-1 they required for many years I ran around 38-1.

Like I say Bill, I have no idea of the saws history apart from what the new owner says he did for the last couple of tanks to run through it and that is hearsay= but I do believe he has the experience to be able to mix the 40:1 he says he was running in it and was using quality oil.

 

[Huskybill]

I sold a good running dirtbike to a kid once and explained how he needed a mixing ratio cup to mix his oil ratio. I road the bike for months never one problem. The second day he over heated it so bad the crankbearing had play between the races. I checked the fuel it was clear fuel. No oil mix. He guessed at mixing by the color. The ign flywheel was so loose at the crankbearing it struck the stator and ripped the bolts out of the case. Mix by the color of the fuel. That’s a new one on me.