550xp mkii needle bearing conundrum

[stewmo]

9 hours ago, Trailoftears said:

As far as I understand it,the spindle bearing cage only spins at idle when v.little heat is generated-is that item in the piccy a metal orplastic cage out of interest?It could be either the drum has interior eccentric internal wear,or looking on the black side- the crankshaft isnt running true?

It’s plastic…..could be wear on drum…..?

[stewmo]

9 hours ago, Dan Maynard said:

And you say the saw is years old so something has definitely changed. Have you recently changed the chain, bar, sprocket or clutch drum?

Will have to look back at my service record and see if any correlation 

[coppice cutter]

What make of bearing are you using?

[peatff]

Take your oil pump drive out as well and check the pump as it looks like it all got hot and is probably melted together. That would explain the stalling and running chain on tick over.

[stewmo]

1 hour ago, coppice cutter said:

What make of bearing are you using?

Husky genuine 

[stewmo]

19 minutes ago, peatff said:

Take your oil pump drive out as well and check the pump as it looks like it all got hot and is probably melted together. That would explain the stalling and running chain on tick over.

I’ll check that. 

[Dan Maynard]

2 hours ago, peatff said:

Take your oil pump drive out as well and check the pump as it looks like it all got hot and is probably melted together. That would explain the stalling and running chain on tick over.

That's a good idea, I bought a secondhand Mak 9010 which had a knackered oil pump and the needle bearing was also melted.

 

As above, this bearing only sees motion when the saw is idling so shouldn't get hot. When you cut the clutch grips and the outside and inside go round together.

 

I think the early 261 were said to be down to oval hole in the drum rather than oval crank, but the effect of eating bearings was the same. Thinking if you've changed the drum might be the issue?

[Trailoftears]

I struggle with the concept of a plastic cage tbh,but they all seem to do it.My newish ms261 and slightly older ms441 both have them.Miniscule weight saving,penny-pinching?

Just from an engineering point of view I find it offensive.

[Dan Maynard]

6 hours ago, Trailoftears said:

I struggle with the concept of a plastic cage tbh,but they all seem to do it.My newish ms261 and slightly older ms441 both have them.Miniscule weight saving,penny-pinching?

Just from an engineering point of view I find it offensive.

Why? It's not guaranteed to stay greasy, I'd rather have a plastic cage than bit of metal scraping around the end of the crankshaft. Likewise the rollers aren't too hard, you want them to absorb damage rather than the crank.

 

I've often wondered about replacing the bearing with an igus bush but I think keeping the same clearance over the temperature range could be a problem.

[Trailoftears]

Well maybe re: a metal cage,but after all its the needles that fly all over the shop given failure.Also to grease or not to grease?Some say yes,some say no.I've examined brand new saws with absolutely no visible grease straight from the factory.On the other hand I've serviced friend's saws with clumps of congealed grease all over the shop-i.e,in and on clutch area.If in normal use the cage experiences minimal heat,it shouldnt need any grease?On the the other hand if you-shall we say assiduously over grease it and something goes wrong,causes heat-then presumably liquid grease flows into the clutch etc.