MS 440 compression
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mheim1
Addicted to ArboristSite
It'll run, but it might be time for new rings.
I'm typically happy with my saws if the compression is above 150.
I'm typically happy with my saws if the compression is above 150.
Wow another first poster. why did you take the compression reading? Is the saw running differently that you think it should? Did you take the compression reading lately in you car or truck? The saw is worth what? Maybe $450 and your car/truck maybe $10,000. But hey let's Keep a compression reading on the saw! Sheesh.
135 is quite low. It should be 150+.
???
The saw is for sale, and was told the compression reading was 135. And the claim was it was in the normal range.
After reading a few other threads where readings were up to 185, thought I would ask the more mechanical people.
After reading a few other threads where readings were up to 185, thought I would ask the more mechanical people.
I just took mine apart my compression was about 140. Once your in there check the piston and cylinder.
Put the rings in your cylinder and check the ring gap it should be .015 if its more your due for rings.
Baileys has caber rings for about $15.
Put the rings in your cylinder and check the ring gap it should be .015 if its more your due for rings.
Baileys has caber rings for about $15.
Brad you forgot our discussion a while ago about the complexities of taking a correct compression reading and how it may affect saws. You are now telling him that 15# difference will make something to worry about? You didn't ask him the method of getting his "numbers" questions. This is his first post. Are you sure he got it right? Mike
nmurph
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Ah-key-tah-san, there is a right way to take a compression reading. If it was done correctly, then 135psi is low. I would be looking for 150-160psi.
Here's what you need to know-
does the gauge have a shrader valve at the end?
is the hose relatively short? a three foot hose will not give an accurate reading on a saw.
has the saw been run recently? an oil film on the cylinder improves the reading.
was the test done on a hot or cold saw? reading will decrease on a hot engine.
and...
most importantly...
did they pull the rope until the numbers stopped climbing?
Here's what you need to know-
does the gauge have a shrader valve at the end?
is the hose relatively short? a three foot hose will not give an accurate reading on a saw.
has the saw been run recently? an oil film on the cylinder improves the reading.
was the test done on a hot or cold saw? reading will decrease on a hot engine.
and...
most importantly...
did they pull the rope until the numbers stopped climbing?
jus2fat
Two Harley Fatboys
The way I read the question is...the OP is looking to maybe buy this saw..??
He is taking the word of the seller of the compression reading = 135lbs.
To the OP: You need to take a compression reading yourself..correctly..
(pull spark plug..put on the choke and pull a few times to lube cylinder and rings..
take choke off and put on/off switch in off position..install compression tester..
pull starter rope as many times as it takes until compression reading stops rising)
That will be your true compression. If you don't have a compression tester..
You can get a loaner at Advance Auto..Auto Zone..O'Reilley Auto...etc.
Doing that and the reading is 135 lbs. You will need to install new rings soon..!!
J2F
He is taking the word of the seller of the compression reading = 135lbs.
To the OP: You need to take a compression reading yourself..correctly..
(pull spark plug..put on the choke and pull a few times to lube cylinder and rings..
take choke off and put on/off switch in off position..install compression tester..
pull starter rope as many times as it takes until compression reading stops rising)
That will be your true compression. If you don't have a compression tester..
You can get a loaner at Advance Auto..Auto Zone..O'Reilley Auto...etc.
Doing that and the reading is 135 lbs. You will need to install new rings soon..!!
J2F
on a saw that size 135 is low you should be seeing 150-170 its time for some rings,,,very easy to do and they are cheap... on smaller saws that might be a normal reading,,i have a 017 that pulls 130 and it runs great.....if u can get it for cheap i saw go for it:hmm3grin2orange:
CWME
ArboristSite Guru
$14.99 for a set at Baileys, $5.99 per ring at Northwood Saw.
Yotehunter66
ArboristSite Member
What the F*&*k! Not everybody was born a genious. Maybe the admistrators could see fit to start us all out at 1000 post so newbies won't be recognized. If you can't offer someone good advice then stay out of the post.
nmurph
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What the F*&*k! Not everybody was born a genious. Maybe the admistrators could see fit to start us all out at 1000 post so newbies won't be recognized. If you can't offer someone good advice then stay out of the post.
Easy, he's had his coffee and meds and he has mellowed.
What the F*&*k! Not everybody was born a genious. Maybe the admistrators could see fit to start us all out at 1000 post so newbies won't be recognized. If you can't offer someone good advice then stay out of the post.
No worries - easy to ignore when people don't have anything real advice to add
044 Compression
So his compression is at 135 psi how much is that going to affect the ability for the saw to cut say 2.5 ft diameter hardwood? I know the more compression the better but how much of a difference is it going to make compared to 150 or so.
Not to hijack this thread but the reason I ask is because I have an 044 that has about the same compression and I recently got asked to buck a number of trees that are down on the ground at my friends girlfriends property. Not going to be doing this job though for about three weeks though. Will my saw be fine or is time to drop the big bore kit in it?
So his compression is at 135 psi how much is that going to affect the ability for the saw to cut say 2.5 ft diameter hardwood? I know the more compression the better but how much of a difference is it going to make compared to 150 or so.
Not to hijack this thread but the reason I ask is because I have an 044 that has about the same compression and I recently got asked to buck a number of trees that are down on the ground at my friends girlfriends property. Not going to be doing this job though for about three weeks though. Will my saw be fine or is time to drop the big bore kit in it?
nmurph
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If you have used the saw as it has lost power, you probably don't realize how much power you have lost. I wouldn't use the BB kit unless you cylinder is bad, I would just replace the piston.
And take the base gasket out but measure the squish band ,to get more compression.
Rusty-880
ArboristSite Member
Depending how the comp tester is designed 135lb could be pretty high. I took the base gasket out of my 880 and took .022" off cylinder giving .018" piston to head clearance. With conventional auto tester I got 135. Theoretically it had bad comp and low power. In reality you had to be a little carefull pulling it over. Best best, dont press decomp valve and pull it over, tell you if it is good comp (within reason ofcourse).
