ID cylinder.

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haha yep. almost shat myself when it showed up, but its definitely 52mm
Hmm. In that case, my guess is that when a Mahle customer requested a variant of an existing casting, in this case a 45mm bore version of a P5000 cylinder with a decompression fitting, rather than change the number on the flange, they just added another '+' or two to the variation panel.
And conversely, if your '54' cylinder was ordered as a replacement part after 281 production had ceased, it could be that it was cast in the then current 288 tools but with the 281 sand/dolly in the bore. (Purely speculation.)
 
Hmm. In that case, my guess is that when a Mahle customer requested a variant of an existing casting, in this case a 45mm bore version of a P5000 cylinder with a decompression fitting, rather than change the number on the flange, they just added another '+' or two to the variation panel.
And conversely, if your '54' cylinder was ordered as a replacement part after 281 production had ceased, it could be that it was cast in the then current 288 tools but with the 281 sand/dolly in the bore. (Purely speculation.)
that i dont know, but i assumed it had tsomething to do with sharing molds
 
Ok ......so I been following this....I've played in this round of cyls before with the Husky 55EPA, the Partner 500, 5000 and 5000+ and the Jonsereds 490 and 590 cyls. There is no way to actually separate some of these cyls by casting numbers and as such they have very different porting and timing numbers...decomp valves or not....

Now this may not be totally accurate and I am certainly willing to listen to different opinions, but here goes....the 500 partner is 44mm open port....the 5000 and 5000+ are 44mm closed port as is the 490 Jonsereds........however the 590 Jonsereds is 45 mm closed port very much like the Husky 55 EPA cyl...though not identical...it really ripps compared the closed port 490/5000/5000+......as does the 55 EPA.....which is 45mm as well. I would have to take apart saws to verify the Mahle numbers but am pretty certain how this goes.....
 
Ok ......so I been following this....I've played in this round of cyls before with the Husky 55EPA, the Partner 500, 5000 and 5000+ and the Jonsereds 490 and 590 cyls. There is no way to actually separate some of these cyls by casting numbers and as such they have very different porting and timing numbers...decomp valves or not....

Now this may not be totally accurate and I am certainly willing to listen to different opinions, but here goes....the 500 partner is 44mm open port....the 5000 and 5000+ are 44mm closed port as is the 490 Jonsereds........however the 590 Jonsereds is 45 mm closed port very much like the Husky 55 EPA cyl...though not identical...it really ripps compared the closed port 490/5000/5000+......as does the 55 EPA.....which is 45mm as well. I would have to take apart saws to verify the Mahle numbers but am pretty certain how this goes.....
i think thats 100% correct as fas as ive heard. a measurement of the bore is whats needed. and the number cast into the cylinder base is not 100% accurate all the time on the actual diameter.
 
i think thats 100% correct as fas as ive heard. a measurement of the bore is whats needed. and the number cast into the cylinder base is not 100% accurate all the time on the actual diameter.


Definitely.....the bore measurement is needed.......but even so, Niko And I went round and round about this years ago and in the end it was clear as mud......so many variations in the same castings......really have evaluate each cyl as a separate unit....as it might be...
 
OK I took the time to measure that cylinder this morning. I got roughly 1.750 inchs.

On the metric conversion chart that comes to 44.45 MM to be 44 MM the inch measure would have been 1.73 inchs.

Close enough I feel to call it 44 MM.

With that in mind where should I look for a new 44MM piston and ring(s)

:D Al
 
OK I took the time to measure that cylinder this morning. I got roughly 1.750 inchs.

On the metric conversion chart that comes to 44.45 MM to be 44 MM the inch measure would have been 1.73 inchs.

Close enough I feel to call it 44 MM.

With that in mind where should I look for a new 44MM piston and ring(s)

:D Al
If it’s over 44 mm, it’s likely a 45 mm, and closed port makes it the piston that Husky no longer has in stock. Even the aftermarket ones are hard to come by, Little red Barn is a supplier that I used to get that particular piston.
 
If it’s over 44 mm, it’s likely a 45 mm, and closed port makes it the piston that Husky no longer has in stock. Even the aftermarket ones are hard to come by, Little red Barn is a supplier that I used to get that particular piston.
I'm not convinced that a measurement slap bang between 44 & 45 is conclusive. I'd try to find a Husky 154 or 254 piston to see if it fits, or a new 500, 5000 or Husky 50 ring in order to measure the end gap.
 
Well my measureing tool was not state of thre art digitl. Just a plain old steel stright edge i use for wood working.

:D Al
 
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:D Al
 





But I am alley yooper. I did say the saw was a 55 EPA, I am told it is different than a regular 55 or a rancher 55


:D Al


That it is.......almost exactly the same as the 590 Jonsered.....45mm @ 51cc........nothing at all like a 55 or 55 rancher......smaller displacement but much more power and rpm.
 
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