been running one for about a year now, great saw but super heavy and drinks gas, I converted mine to run 3/8" 0.050 chain on a 20" bar as an every day work saw
runs a normal rim sprocket (same exact one that comes stock on a 500i)
starts easy, minus the stupid amount of compression, good luck if you are hot and tired (which you probably are if you have to get a 120cc saw out)
in reality, if I was going to run the recommended 42" bar, i would buy a 661 or a 395XP long before an 881, I got this to eventually put a 6ft bar on, the 42" is just too dang short for a lot of stuff im doing (sometimes double cutting limb wood on red oaks)
I should mention, this is the ONLY saw I run my own mix fuel in, just because it burns about 2 gallons per hour, seriously burns more fuel than my chipper does!
might get a west coast barkbox and 3pt dogs for it eventually