motorman1
ArboristSite Operative
I guess me too. Have never bought a wrist pin specific size 044/440 jug and have built dozens without a single mishap. Guess I must have been unusually lucky?
044 burned jug and piston.
- Thread starter Brewdawg
- Start date
Help Support Arborist Forum:
drf255
BAD CAD
Pretty sure the amount of skirt difference is negligible.
It’s 100% certainly in a factory bulletin not to use a 12mm jug over a 10mm piston for the reason of the skirt and pin vs. port sizes. Meteor pistons sometimes have wider than oem skirts (on 046 for sure) but I believe oem 10 vs 12mm slugs had the same widths when I checked them.
It’s 100% certainly in a factory bulletin not to use a 12mm jug over a 10mm piston for the reason of the skirt and pin vs. port sizes. Meteor pistons sometimes have wider than oem skirts (on 046 for sure) but I believe oem 10 vs 12mm slugs had the same widths when I checked them.
drf255
BAD CAD
Good information. Thanks! I sourced a factory 10mm slant fin Mahle jug. Should be here in a couple days. It's used but from the pictures looks good. Was planning on a meteor piston but hmmmm.....
So looking at the spark plug that came out of the saw it looks chocolate brown. Pretty much the same color that I shoot for when jetting a dirt bike. Still seems to me that it has a too lean condition going on though.
So looking at the spark plug that came out of the saw it looks chocolate brown. Pretty much the same color that I shoot for when jetting a dirt bike. Still seems to me that it has a too lean condition going on though.
motorman1
ArboristSite Operative
I've always just ordered 040/440 jugs off eBay and they never, TMK, have indicated wrist pin size in their advertisements. I've rebuilt almost all of my 044/440 saws with Meteor pistons, or the correct pin size used OEM pistons with zero problems. Just sharing my experience and apparent luck, nothing more, as I'm no expert here.
drf255
BAD CAD
I can’t find my pics at the moment, but Meteor 10 and 12mm pistons have the same skirt and pin spacing, both wider than oem. It appears that their 10mm casting is the exact same casting as their 12mm casting with the exception of the wrist pin bore.
However, because it’s the same casting, the inner pin bosses just as wide in both castings. The 10mm small rod end is narrower in the 10mm saw, so it allows the wrist pin bearing to move around side to side slightly out of the rod bore. A factory 10mm piston has narrower pin bore spacing and can’t be slipped onto a 12mm connecting rod at all, regardless of pin diameter.
Many call this a theoretical issue but also agree they’ve never seen a real world failure. So the meteor 10mm piston is a quick “cheat” to make a 12mm top end safely work on a 10mm saw.
Again, the factory probably uses much more conservative measurements than we do and I’d venture to bet that a 10mm OEM piston would work in a 12mm jug just fine.
However, because it’s the same casting, the inner pin bosses just as wide in both castings. The 10mm small rod end is narrower in the 10mm saw, so it allows the wrist pin bearing to move around side to side slightly out of the rod bore. A factory 10mm piston has narrower pin bore spacing and can’t be slipped onto a 12mm connecting rod at all, regardless of pin diameter.
Many call this a theoretical issue but also agree they’ve never seen a real world failure. So the meteor 10mm piston is a quick “cheat” to make a 12mm top end safely work on a 10mm saw.
Again, the factory probably uses much more conservative measurements than we do and I’d venture to bet that a 10mm OEM piston would work in a 12mm jug just fine.
brandonstc6
Addicted to ArboristSite
Meteor 12mm pin pistons are fine. Meteor 10mm pin pistons are the one where the spacing between the pin bosses is too much. The meteor piston is fine for a 12mm pin saw.
And definitely you need to do a pressure/vacuum test.
Sent from my iPhone using Tapatalk
Well I think it's safe to say the serial number doesn't lie on this one. It is indeed 12mm wrist pin saw. Waiting for the new used oem jug to show up. Am I leaving anything on the table as far as being able to do a better job widening the ports if I do run a meteor piston? I noticed the shape of the skirts are slightly different.
Attachments
Well guys( and gals?) I'm ordering parts tonight. Going with a meteor piston from saw again and planning on oem clips and the thin base gasket. Was thinking about doing a dual port port muffler and bigger better air filter. Any suggestions?
Mighty Vac 8500.
cus_deluxe
Commie Satan turd
And yet after building “dozens” and faced with a technical bulletin from the manufacturer you seem to stick to your skepticism.
Its a gamble, make it if ones wants.
Check the squish, soft electrical solder is good enough, I use .025 dia for the first go round.
Since the 10mm OEM slug is NLA, meteor is one option, so anybody use a spacers for the needle BRG?? If so what you using,, pics? Source?
Asking as im just going to put a meteor 10mm slug in a old slant fin,,
Or just run it,,
Asking as im just going to put a meteor 10mm slug in a old slant fin,,
Or just run it,,
Correct me if I am wrong but I don't think spacers are really needed from what has been discussed. Mine is a 12mm so the point is moot for me.
