It's very smooth inside, no scoring at all, but it looks like the plating is worn through? Or what am I seeing? The dark parts wont come off. I hope these pics are good enough.
It's off a 970 pioneer if that makes any difference.
Is this jug worn out or what?
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It's very smooth inside, no scoring at all, but it looks like the plating is worn through? Or what am I seeing? The dark parts wont come off. I hope these pics are good enough.
It's off a 970 pioneer if that makes any difference.
Hard to tell from picts Chris, the way I measure a cylinder is take a new ring and insert it, square it with the piston up just above the exhaust port and measure the end gap. .009 is real good-.012 starting to get sloppy. A new piston should show .003 -.004 clearance at the skirt. Then there is the bore gauge but first you need one, I can send you one over.
Pioneerguy600
Pioneerguy600
Last edited:
Is it discoloration or is the
chrome actually worn off.
I have seen cylinders that look
like yours but the chrome was good.
Lee
chrome actually worn off.
I have seen cylinders that look
like yours but the chrome was good.
Lee
PA Plumber
Addicted to ArboristSite
Good thread.
I have an 044 that is very nice cosmetic shape, but can only get around 120 psi compression.
Flex honed the cylinder, thew in some new rings, and am still only getting 120 psi.
I'll try the ring gap measurement technique, and see how it turns out.
Kinda stinks. It's a 10mm wrist pin and the cylinder looks great.
I have an 044 that is very nice cosmetic shape, but can only get around 120 psi compression.
Flex honed the cylinder, thew in some new rings, and am still only getting 120 psi.
I'll try the ring gap measurement technique, and see how it turns out.
Kinda stinks. It's a 10mm wrist pin and the cylinder looks great.
I don't get the horizontal black lines, is what got me confused I guess. This saw sat for a very long time. I was just wondering if it was worth saving, I don't need it for anything right now. I'm pretty sure I can get a bore gauge from our shop Jerry, but thanks for the offer.
Just looks odd.
Just looks odd.
Scooterbum
Addicted to ArboristSite
The plating in the bore can discolor like that and still be good.
Think about the exhaust pipes on a motorcycle.
Think about the exhaust pipes on a motorcycle.
Scooterbum
Addicted to ArboristSite
Have you checked the squish?
How does it run?
I had an early 044 with compression in the upper 120's that screamed until a friend straight gassed it.
Sprintcar
Chainsaw Slut
Chris it's kinda hard to tell in the pictures but I rebuilt an XL-Super 2 that looked allot like that cylinder. The hardened chrome was discolored around the exhaust port but didn't have any peeling. After new rings pulled cold at around 140. Ran O.K, nothing to write home about. Clean her up and use Jerrys recommendation on ring gap. He has forgot more about saw than I will ever know.
PA Plumber
Addicted to ArboristSite
I gave the saw a try cutting wood this past Saturday.
It starts easily, but dies in the cut.
Pulled off all the rubber this morning and found the fuel line has collapsed.
Ordered all new rubber from a local Stihl dealership.
I did check the ring gap. It is between .028 mm and .024 mm.
Do I need to re-flex hone the cylinder. Not even a 1/4 of a tank of fuel through the last hone job?
Thanks.
Scooterbum
Addicted to ArboristSite
I wouldn't rehone. That plating is real thin.Once it's gone that's it.
Wait for the new rubber.
It's hard to tell for sure from the pics, but I don't see any chrome worn through. The darker areas are just where the piston and rings run and polished the bore.
:agree2:....Generally, dark areas aren't the concern. It's light coloured spots where the aluminum is showing through, that you look for.......Again, it's a little hard to tell from your pics, but It looks ok.
PA Plumber
Addicted to ArboristSite
Will do.
I have a very nice condition 359 that I threw a new piston/rings/cylinder/cylinder gasket in a few days ago. Compression was only 110 psi after the rebuild and it runs terribly.
Rats, another one of these? I'm guessing now is a good time to learn how to use the pressure/vacuum pump that's been sitting in the garage?
