I have a 20" Forester bar on 4 of my Partner 5000's and the one I had been running last week was having chain issues. The chain would be tight then loose so today I did a search " saw chain tight then loose" and did some reading. It happens enough that there were some good reply's .
So the jist of it was maybe ,..1) wrong chain, sprocket, and or tip combination. 2) little or no oil. or 3) Bent crank. It turned out that some how I had turned the oil adj screw down some so I opened it up. While I was there I took off the clutch checked the sprocket against the driver's and the tip all are .325 (Stihl full chisel b.t.y)
While I had the bar off I noticed something that is most likely on all Forester bars,.. a very small oil hole in the bar. It is like punched into the bar channel at a 30 degree angle and maybe a 1/16 opening. I knew that on my Windsor, Oregon, and other bars the hole is much larger. So I drilled it out to what turns out to be 17/32 I am in hopes this will be a big help. Not only is the hole small but like I said it appears to be punched into the bar and the ragged left over edge is in the hole as well. I have not run them enough to tell but I hope this is the only issue I discover. I only cut about 14 cord a year but this year I cut 4500' of saw logs as well ( not with one of my forester bar's though ). I did most of my work with a 500 and a Windsor bar. Thought I'd share what I discovered if YOU have any Forester Bars,... check your oil hole's Jeff View attachment 302246View attachment 302250
So the jist of it was maybe ,..1) wrong chain, sprocket, and or tip combination. 2) little or no oil. or 3) Bent crank. It turned out that some how I had turned the oil adj screw down some so I opened it up. While I was there I took off the clutch checked the sprocket against the driver's and the tip all are .325 (Stihl full chisel b.t.y)
While I had the bar off I noticed something that is most likely on all Forester bars,.. a very small oil hole in the bar. It is like punched into the bar channel at a 30 degree angle and maybe a 1/16 opening. I knew that on my Windsor, Oregon, and other bars the hole is much larger. So I drilled it out to what turns out to be 17/32 I am in hopes this will be a big help. Not only is the hole small but like I said it appears to be punched into the bar and the ragged left over edge is in the hole as well. I have not run them enough to tell but I hope this is the only issue I discover. I only cut about 14 cord a year but this year I cut 4500' of saw logs as well ( not with one of my forester bar's though ). I did most of my work with a 500 and a Windsor bar. Thought I'd share what I discovered if YOU have any Forester Bars,... check your oil hole's Jeff View attachment 302246View attachment 302250