MS260 vs MS261 crankshaft bearing differences

[greg_bbs]

Would anyone know what the difference is between the crankshaft bearings on a MS260 and a MS261?
The Stihl part numbers are slightly different but both bearings measure exactly the same! The original bearings in the 261 are plastic caged just like the 260. A few aftermarket suppliers are stating the 260 bearings also fit the 261!
My local Stihl dealer couldn’t tell me what the difference is. I want to buy OEM but the 260 bearings are a fair bit cheaper.

 

[drf256]

I’ve done a bunch of 026/260, but never had to rip a 261 apart yet.

The 260 shares the same PTO bearing with the 036/044/046 except for one not having a grooved outer race. The one with the grooved race fits them all, 024-046.

The 260 flywheel side bearing is unique. The number slips my mind, but it’s basically a thinner 6202 bearing. The fly bearing for 034-046 is a standard 6202.

I am unsure what either side of a 261 calls for. It’s been posted here that the 462 has the same physical size bearing as the 024-046 but it’s lighter in weight. Just like the case screws, they may have made a lighter in weight bearing that’s physically the same size as the older bearing. If that’s the case, use the old one and add a few grams of weight to an already light saw.

Can you post pics and dimensions of the old bearings? We can reference the 026 bearings for you and see if the same.

 

[greg_bbs]

I’ve done a bunch of 026/260, but never had to rip a 261 apart yet.

The 260 shares the same PTO bearing with the 036/044/046 except for one not having a grooved outer race. The one with the grooved race fits them all, 024-046.

The 260 flywheel side bearing is unique. The number slips my mind, but it’s basically a thinner 6202 bearing. The fly bearing for 034-046 is a standard 6202.

I am unsure what either side of a 261 calls for. It’s been posted here that the 462 has the same physical size bearing as the 024-046 but it’s lighter in weight. Just like the case screws, they may have made a lighter in weight bearing that’s physically the same size as the older bearing. If that’s the case, use the old one and add a few grams of weight to an already light saw.

Can you post pics and dimensions of the old bearings? We can reference the 026 bearings for you and see if the same.

Thank you @drf256
I never thought to weigh them. I’ll get my scale out. The generic 024, 026, 240 and 260 flywheel side bearing is a 16002. Unfortunately, here in Canada, SKF, Nachi, NTN, etc. all cost more than OEM and shipping from the US is expensive.

 

[greg_bbs]

The clutch side bearing on the 261 is 0.9 grams heavier. The flywheel side bearing on the 261 is 0.3 grams heavier.

 

[greg_bbs]

I just spoke to Stihl Canada technical department and was told they’re different bearings. All 4 numbers are available as current numbers. I was told that Stihl Germany won’t divulge the difference. The tech told me dimensionally they are the same, but there is
“some kind of difference” in either the load capacity, clearance rating or heat resistance.

 

[Mastermind]

I just spoke to Stihl Canada technical department and was told they’re different bearings. All 4 numbers are available as current numbers. I was told that Stihl Germany won’t divulge the difference. The tech told me dimensionally they are the same, but there is
“some kind of difference” in either the load capacity, clearance rating or heat resistance.

I believe the 261 bearing has an extra ball.

 

[greg_bbs]

I wonder if the MS261 bearings are a C3 rating?

 

[Mastermind]

I wonder if the MS261 bearings are a C3 rating?

I'm sure. Industry standard.

 

[greg_bbs]

I believe the 261 bearing has an extra ball.

I’ve got the used bearings out of both saws and they have the same number of balls.
I don’t have new 261 bearings on hand to confirm the number of balls in the new ones. The Stihl tech person told me the 261’s have used the new bearing since day one!

 

[greg_bbs]

Apparently, a lot of the MS 261’s had bearing trouble with the big rod end bearing. I wonder if it could have anything to do with the change in the crankshaft bearings either getting tighter when they’re hot or possibly some kind of reverberation that goes through the crankshaft and causes the big end bearing failure!
Just thinking of possibilities!
I am sure I am over analyzing it, but before I put it back together, I would like to know if it would be better to use the 260 Bearings?

 

[Mastermind]

Apparently, a lot of the MS 261’s had bearing trouble with the big rod end bearing. I wonder if it could have anything to do with the change in the crankshaft bearings either getting tighter when they’re hot or possibly some kind of reverberation that goes through the crankshaft and causes the big end bearing failure!
Just thinking of possibilities!
I am sure I am over analyzing it, but before I put it back together, I would like to know if it would be better to use the 260 Bearings?

Define a lot.

I've literally ported hundreds of 261s. I've seen one with a bad bearing.

 

[greg_bbs]

Define a lot.

I've literally ported hundreds of 261s. I've seen one with a bad bearing.

My saw has a bad big end bearing. Other than that it’s from forum searches. I certainly am not going to disagree with you; I respect your knowledge and opinion. Just to finish beating a dead horse, would you recommend using the specified 261 bearings?

 

[Mastermind]

My saw has a bad big end bearing. Other than that it’s from forum searches. I certainly am not going to disagree with you; I respect your knowledge and opinion. Just to finish beating a dead horse, would you recommend using the specified 261 bearings?

I would use the bearing Stihl recommends.

 

[Mastermind]

I have a 261 FWS bearing here.....but not a 260 bearing. Now I'm interested in seeing exactly what the difference is.

 

[greg_bbs]

I have a 261 FWS bearing here.....but not a 260 bearing. Now I'm interested in seeing exactly what the difference is.

Sorry,
If my ocd is contagious.
I have both used ones in my hand and can’t tell the difference other than the 261 is 0.3 grams heavier!

 

[greg_bbs]

I have a 261 FWS bearing here.....but not a 260 bearing. Now I'm interested in seeing exactly what the difference is.

Just brain storming but do you think maybe the plastic cages have a higher heat resistance or are stronger? Do the MS261’s run hotter because of emissions choking them more than the 260’s or 026’s?

 

[Mastermind]

Just brain storming but do you think maybe the plastic cages have a higher heat resistance or are stronger? Do the MS261’s run hotter because of emissions choking them more than the 260’s or 026’s?

If the 261 runs hotter, I think it would be due to the top cover design rather than any sort of restrictions.

 

[drf256]

I’ve seen OEM bearings with 1 more or less balls. Some 6 and some 7. Never knew why.

I thought the early 261 had the soft crankshaft material the made the PTO end wear down from the Clutch drum bearing?