I got dirko coming at napa tomorrow. But dealer says that ring gap is far too big. Those are caber rings so idk why they're so gapped. Got some oem rings on order from the dealer. Fingers crossed
Mysterious Stihl 064
- Thread starter Sunterbach
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Gamma Woods
ArboristSite Operative
That was something I was thinking, but your squish is good so I don't think that's the case.
Your end gap of .032 is huge, we might have found the culprit. I don't have an 064 myself, but with a 52mm bore I think you'd want less than .01, a bit tighter would be better.
Is there a way to improve that or is it just new rings?
I honed out and cleaned the oem cylinder and slapped it back on. It runs!!! Can't tune it to run right though. And if I put too much pressure on the chain in the cut it stops the chain and bogs the saw to death still. Seems low compression still but it runs with a filter so we're getting somewhere.
Still looking at compression in the 95 range. So that checks. I just put my compression tester on my ms 170 and it pulled 125. It runs great so I'm wondering if my tester is testing low
Tested it with a compression tester i know works. Same result. So thats its true compression. THE MYSTERY CONTINUES
Wore cylinder, out of round more than likely with probably some taper
Ok that could make sense. But do you know why I would have these problems with the new meteor jug too?
Just because it's new don't mean anything. I rebuilt a 288xp using a new OEM mahle piston and cylinder set and It would only give me 120 psi. After some heated arguments with tech support, they traded me out, and the replacement had 150 psi.
Gamma Woods
ArboristSite Operative
Is the 95 PSI with the OEM cylinder and Meteor Piston/rings?
That's the most promising story I've heard in weeks about this.
Yes! But I just ran it in some wood lightly for about 30 minutes off and on and I got 105 now after letting it cool.
Gamma Woods
ArboristSite Operative
I figured as much, I'm pretty much positive it's the rings. For ***** and giggles you could try transferring the rings off the old piston if they fit the new piston, but that would just be part of the testing to confirm the new rings are the problem. I think that step is unnecessary at this point, you're going to want some new rings regardless, but it can give you something to do while they ship lol.
glock37
Addicted to ArboristSite
Meteor cylinder kit may have huge squish
Meteor pistons are fine to use there next too oem to use
Aftermarket cylinder kits are all over the map on tolerances
We get about 200 lbs with squish band s cut and bases cut ending about 22 squish on 064 with dirko base sealant
If still have a problem think about sending it out too get some port work done and some machining
064 s run great
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Its funny I had the same two ideas. I'm gonna do both. I have new rings coming from the dealer (who knows when the heck those will come in) and I'm talking to my machinist buddy about decking .020" of the cylinder. From what I've read, it won't put the ports too low and no additional machining needs to be done.
105psi is worn out saw pressure, that’s obviously not your case. My 038mag with an original top pushes 180, that 064 should be right there too. Sounds like you’ve covered your bases. Keep us updated
I'd check your squish before you go cutting the base, that way you can do a more accurate job when you're doing the actual machine work.
I did. Squish was .0425 with the .5mm gasket. I'm taking 20thou off. If it somehow doesn't work cause I measured wrong, I can put the 1mm which would add almost 20thou back onto it
To everyone who has been helping me with this PITA saw: what all would cause this low compression? I think I know the whole list, but I must be missing something. I have compression problems with both the OEM and Meteor cylinder. So I know it's not a bad cylinder. (probably) I've checked ring gaps: within spec. No vac or air leak so no bad seal or rubber. It's not the spark plug and there's no hole for decomp valve.
I agree it's a compression problem now, but I don't know where from. Also, if anyone has an OEM piston for this saw, could you post the dimensions of it? I think the most important thing I need to know is wrist pin to top of piston? Gosh who knows, just shooting in the dark at this point.
Thanks yall.
I agree it's a compression problem now, but I don't know where from. Also, if anyone has an OEM piston for this saw, could you post the dimensions of it? I think the most important thing I need to know is wrist pin to top of piston? Gosh who knows, just shooting in the dark at this point.
Thanks yall.
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Some Italian with a wicked sense of humour put an MS460 piston in the box with an 064 cylinder?
remove the carburetor and muffler and retest compression , piston installed backwards? put a spritz of soapy water at the spark plug threads when testing
Ring end gap should be .010” - .015”. Get that part sorted first. Deleting the gasket should net you about 15 more psi
