Rusty-880
ArboristSite Member
And my stock strong ms361 only made 85psi....
Different testers different readings
Different testers different readings
Just bought a used 440 off ebay. Needed bearings a seals. The saw wont run so I checked the compression. 90 psi cold. I will try new rings before buying a new piston and jug.What should the compression be on the Stihl MS 440? Is 135 too low?
thanks
Pull it apart and inspect.Just bought a used 440 off ebay. Needed bearings a seals. The saw wont run so I checked the compression. 90 psi cold. I will try new rings before buying a new piston and jug.
I know it's already been said, but... If the cylinder is in good shape, there is no good reason to install an AM big bore kit. I would recommend a Meteor piston kit, or just replace the rings with new ones if the piston is still in good condition. There may be a few exceptions, but the OEM cylinder is almost always a better option than aftermarket cylinder kits. A meteor piston is usually around $40.If ur pulling apart to put bearings and seals and new rings won't do it to get the compression up might as well put a big bore kit on it. 90 psi is real low. Is it scored a little. I hope u got it at a good price bud. I know 160 to 170 is much
Desired but u can get away with 150 to 155 but if ur going through all the trouble I would want 160 to 170.
surprisingly there was little to no scoring. there is an area where the nikasil is worn down to the aluminum so that could be the culprit. i dont get my rings for a week or so, so i wont know until thenIf ur pulling apart to put bearings and seals and new rings won't do it to get the compression up might as well put a big bore kit on it. 90 psi is real low. Is it scored a little. I hope u got it at a good price bud. I know 160 to 170 is much
Desired but u can get away with 150 to 155 but if ur going through all the trouble I would want 160 to 170
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I was thinking the same for the big bore kit. This thing was 300 bucks, got maybe another 100 into it for seals, bearings, oil pump.If ur pulling apart to put bearings and seals and new rings won't do it to get the compression up might as well put a big bore kit on it. 90 psi is real low. Is it scored a little. I hope u got it at a good price bud. I know 160 to 170 is much
Desired but u can get away with 150 to 155 but if ur going through all the trouble I would want 160 to 170
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the OE piston looks really good so I will see if the new rings work out. I will let you all know what the compression comes up to .I know it's already been said, but... If the cylinder is in good shape, there is no good reason to install an AM big bore kit. I would recommend a Meteor piston kit, or just replace the rings with new ones if the piston is still in good condition. There may be a few exceptions, but the OEM cylinder is almost always a better option than aftermarket cylinder kits. A meteor piston is usually around $40.
make sure it is not lean at that point, recommend tachHello All. I ran a couple of tanks through the new 440, running it easy, not full throttle. Yesterday, I decided to have some fun with it. I do not have a tach, but the saw seems to really take off after about 3/4 throttle. If you have any experience with dirt bikes, its how the YZ250 is tuned. We used to call it "being on the pipe". Does the 440 normally do this? All I can say is, its not like a linear rpm curve that I experience with my 391. Its like the rpm curve is linear, then it goes exponential. It is really an exhilirating feeling.
good idea. i was worried about that. thanks for the recommendation.make sure it is not lean at that point, recommend tach
Thanks. I am glad you knew what I was referring to. I did port and polish the cylinder and port the muffler so I didn't know if that had something to do with it. I never ran a 440 so I wasnt sure ifIt should be pretty linear in the throttle, not "pipey" like a dirt bike at all. You have an issue of some sort if the revs just take off.
Anyone catch this?surprisingly there was little to no scoring. there is an area where the nikasil is worn down to the aluminum so that could be the culprit. i dont get my rings for a week or so, so i wont know until then
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