Got a used 372 last week. The PO must have not thought much of sprocket, chain and bar maintenance. The bar had a wicked burr to it. The chain Roberts are completely done. The rim was so worn the dl fig holes into the drum! Wow
Replace it immediately , or as soon as possible!
Rim sprockets are very affordable and easy to come by.
The cast quality of Oregon and Carlton sprockets seem similar enough , with Carlton sprockets showing some minor visual cast defects that should not affect the sprockets durability/functionality.
Carlton sprockets are not much cheaper then Oregon (PowerMate) ones , so if You want "to be sure" get a Oregon sprocket.
That sprocket does not have "wear-depth indicators" , as such I dare assume it is the saws original sprocket.
Lol! I didn't even know those were a maintenance item til I found this site.
How much wear is considered acceptable?
Replacement Oregon rim sprockets feature "wear-depth indicators" to help identify a worn sprocket , or at least all those that I purchased thus far!
Also , my Sachs-Dolmar 105 manual states (spur) sprocket replacement when wear reaches 0.2mm (~.0048") of dept.
"Rule of thumb" replacement recommendation for my Dolmar PS-6400/7900 says every 2 chains or sooner.
Some of my sprockets:
- Original Dolmar/Oregon "PowerMate" rim sprocket of my Dolmar PS-6400, has worn out 2 chains , radially ported but features no "wear-depth indicators" , 7 tooth , 3/8":
- Replacement Oregon "PowerMate" rim sprocket , has worn out 1 chain , radially ported & features "wear-depth indicators" , 7 tooth , 3/8":
- New Oregon "PowerMate" rim sprocket featuring radial ports & "wear-depth indicators" , 7 tooth , 3/8":
- New Carlton rim sprocket , features radial ports but no "wear-depth indicators" , 7 tooth , 3/8":
- As new Carlton rim sprocket , features no radial ports nor "wear-depth indicators" but has a "windowed" design , 8 tooth , 3/8":
My Dolmar PS-7900's original 7 tooth rim sprocket and its accompanying original first now worn chain have left small dimples in the drums spline (just noticed it the other day)!
That never happened on my PS-6400 even after wearing out 2 chains on 1 sprocket.
I guess the higher power of the saw allowed for more aggressive usage of the saw (read dogging the saw through a cut rather then allowing self-feeding) and thus caused heavier wear off the sprocket and the drive links touching the drums spline at the end of the sprockets & chains life.