On Wednesday, April 21, 2021 at 11:21:13 AM UTC+1, T i m wrote:
On Tue, 20 Apr 2021 13:48:55 -0700 (PDT), Chade
wrote:
Hi all

My sthil ms260 was starting fine but overheating and cutting out. My local garden machinery repair place told me it was because the piston/cylinder was scratched
Do you know how they knew that?

They said they had removed the muffler and so looked directly at the piston..

and as this would probably have damaged the rod it was beyond economic repair.
'Probably'?

Knowing nothing about engines, but surprised by the cost of new chainsaws, I spent some time on google and youtube. I ordered a new crankshaft, piston, various bearings, gaskets and cylinder assembly.
Ouch (unless they were Chinese clones)?

Apart from one bearing they were third party at less than a third the cost.

It took me alot longer than I anticipated but the chainsaw is now back together with all the bits replaced.
They are quite straightforward once you are used to them. Daughter had
to demonstrate basic engineering skills on her MS260 as part of one of
her chainsaw tickets (CS30?). [1]
I was happy with everything but now realise that with all the jumping about on youtube I have greased one bearing too many. As well as the bearing I should have greased (in the sprocket) I have also lightly greased the little end bearing with lithium grease.
Are these 'plain bearings' (metal on metal) or 'open' (presumably)
roller or ball bearings?

Pin roller bearings. I guess they would be classed as open.

I know really I should take it all apart again to clean it and put it all back together, but if I started and ran the saw as it is and everything else was right would it do much harm?
The only place I can think of where you wouldn't want grease is on the
centrifugal clutch shoes and they are fairly easy to get to if you
thought there was a chance.

The clutch shoes are grease free.


If they did have grease on them some brake cleaner might get it off or
when I was a lad I'd boil them in some washing detergent. ;-)

Cheers, T i m

[1] When taking their chainsaw maintenance test (at the Arb College)
the group all worked at the same time and were 'tested' on completion
of the re-assembly.

One lad presented his saw and the examiner questioned 'if he was
finished'. He said he was, so he repeated the question ... 'are you
sure you have finished', same reply. So he failed him for having the
chain on back to front. ;-(