See how low you can go with the rakers and still maintain optimal 10k to 11k rpm (or whatever the number with a 261) in wood with the .325 20" that you have. If it handles 40 thousandths or lower, should handle 3/8ths at 25 thousandths on a 20" bar and/or .325 on a 24"/25" bar.
A 3/8-7 is kinda standard. 3/8-8 will move the chain one more drive link per crank revolution = faster chain speed.
I'll check and see what is on my 026 tomorrow. The sprocket/bar/chain on that saw is perfect. The saw screams in cut if I turn it up (I don't run it up there) with .40 rakers. I'm cutting 16 inch hard wood with the tiny 49cc saw and it rips! If I was you, I would try to find a windsor bar on ebay. They are much less expensive and are much better than stock stihl bars.
The sprocket on my 026 is a 7 tooth. That saw runs full comp 3/8 with .40 rakers no problem in hard wood.
(4) advance timing
I like the idea of a base gaskit delete. You fill get more grunt+ more compression. A better muffler would be a great idea to. If you are in this far I would enlarge the transfer ports a little bit. Half of porting is incressing air flow by cleaning up rough surfaces. And/or buy a 044!
Porting/performance mods don't decrees longevity in less you run the saw lean. A good saw man can make a mod saw run for years. Buckin's super turned up 371 was ported 30+years ago. He runs the saw day in and day out and the saw is still in great shape.
amazing fuel. I can walk in from some lite sawing and have a seat in my chair, and my wife doesn’t even notice 
. My wife has a blood hound of a nose on her just sayn! 
I wish there was a way to buy the fuel that’s in motomix and mix our own. I have other 2 stroke machines (Cheap machines). Weedeaters, blowers, etc. and I’d run that in all of them just to avoid smelling like gas.
You wont get carbon if you run even 32/1. I run 20/1 even in my newer saws and I never foul spark plugs. 50/1 has less oil than mixes with lower numbers.50/1 has 50 parts gas to 1 part oil. 40/1 has 40 parts gas to one part oil and so on .I think there is probably a very fine line. We can run more oil and less gas and we get carbon build up. Or we run less oil more gas and get scratches on our piston lol. But isn’t 32:1 more lean than 50:1 since it is less fuel.
I am tempted to just run 50:1 with Honda HP2 dirt bike oil, I bought some just for this. I thought about mixing more oil, but I think HP2 is good enough to work well at 50:1. I’d like to avoid a whole bunch of carbon if possible. I’m spoiled on this odorless Motomix stuff though. I don’t understand why regular gas smells so terrible.
Great advice.
Base gasket delete on the 261 is not something I'd recommend. It has about. 035" clearance with a base gasket. The gasket is .018. The extra compression isn't that important.
That rpm is perfect.I spent a good 25 minutes on tuning the saw today for the first time. My high speed is 100% all the way open, I cannot richen it up anymore (Factory Limiters in place on the carb) (If I install a filter or exhaust, it’s just gonna want more fuel, which I can’t give it) I saw max RPM of 13,860 most of the time with the High speed jet all the way out. I felt a moment where the saw actually started to open up and come to life revving higher and higher easier and easier! It was hitting 13.8K-13.9K and 4 stroking an easier and easier which more or less came out of no where! It was lovely, it seemed harder to rev before and didn’t 4 stroke all that much if at all. My low speed was too rich, and was causing some stalling every 3 out of 10 quick jab and release throttle presses. I leaned the low speed just a tap, and this fixed it. I can see just a little tiny bit of smoke when gassing slightly off idle, and it quickly returns back to idle and no stalling anymore.
I wish I could richer the high speed up just a little more honestly. It’s 4 stroking nicely, and reaches its limit of 13,860 rpm maybe 13,900 at times. But I think 13,500-13,700 would be more realistic for long term usage.
Anyways, what a nice saw! Went through almost a whole tank just idling, and mild revving with a few high RPM hits to check if it was too lean or not, my neighbors probably thought I was insane. Great running saw though! I have to give props to the Motomix fuel as well, that stuff has no smell/odor, doesn’t make your clothes stink at all, the exhaust fumes smell just like a candle burning. You could spill it on your hand and it’s almost nothing there, smells like alcohol or something
and then have 32:1. 
