michpatriot
ArboristSite Lurker
Well I've been tweak'n my 2018 MS880, after much murky fact finding online here's what I've ended up with..I fabbed up a second exhaust outlet using 1\2" stainless pipe. I set it over a 3\8" hole drilled in from the outside of the muffler into the exhaust passage behind the screen so as to retain the screen function. Next I pulled the carb limiters and installed a MS361 coil, and finished up with advancing the timing by filing .040 off the .080 thick crank key. So its a half a key advanced (super scientific). I tuned it in the cut with a 36" bar and .404 full chisel full skip. Absolute night and day between this setup and stock. Crisp throttle response and pulls a 8 pin sprocket pretty well in 30" dry ash with full skip. For those who follow this path I will caution that you need to run good 100% gasoline. No ethanol. I use 91 octane rec fuel from the pump and add octane booster to achieve around 95-96 octane. Setup like I have described you have the ability to tune in the cut and clearly hear 4 stroking. You also will have the ability to absolutely melt down your saw if you don't adjust correctly. I won't have my saws any other way. This saw is now running like one would expect a new saw to run..it will never be as crisp as a fully port adjusted, squish band worked saw done by any of the masters...but I like it now. I have the 7pin back on and full comp RS .404 back on the 36" bar and will probably save the 8 pin for GTG with a 25" bar but it did pull it surprisingly well. Later this week I have a tachometer coming and will get back with the rpm that its running now..it won't really chance my tune, I like it where its at, but it'll be neat to see the numbers..its a real work saw now.
Joel
Joel