The Stihl MS390. Overweight, underpowered, homeowner turd, it's been called every one of those things. So what's a guy to do if he stumbles on one for a good deal? Ignore it? Heck no! What if the top end turns out to be trashed? Are those aftermarket cylinders any good? You tell me. That's a 20" bar in some variety of maple.
I had an all stock 029 Super for many years... It never gave me any trouble. I ran it on junk oil and ethanol gas @ 50:1, and it pulled a 25" bar for at least a few years. I guess I didn't know any better!
That thing is running pretty good!! I wouldn't throw a 290/310/390 out of my garage. They are some of the most popular saws out there! And for good reason! Looking forward to the "rest of the story"!!
390 is only one in that series that goes with the weight for cc of the saw IMO. The others are heavy for cc, like 290.
So here is what a normal cylinder off of a MS290/310/390 looks like right? And this is what I got out of the box with the HyWay kit. Little different configuration right? Note the large "button" in the transfer ports. They were also present in the intake and exhaust ports. I ground them off and cleaned up the rough casting inside of the intake/exhaust ports. Note that I did not alter the timing or width of the intake/exhaust ports at all. Just cleaned up all the extra material HyWay left in them. One other thing, in this particular case, the cylinder had plating sprayed in EVERYWHERE. Cheap grinding burs need not apply.
The muffler mod is a bit extreme. I guess I don't have a pic but the internal baffle has been completely bypassed and the deflector opened up as much as I dared. Any more and it would look like crap.
The 029, 029 Super, 039, MS290, MS310 and MS390 (Collectively referred to as the 1127 Series.) all weigh in pretty much at the same weight, give or take an ounce or two. So do you want a 14lb 56 cc saw or a 14lb 64 cc saw?
That 460 was a real nice runner. You send that thing to TN yet? I wish 390's ran this good from the factory. To be clear, I think the OEM cylinder would run even better but for about $100 less, this is a realistic alternative if you have the ability to smooth it out. I didn't use anything fancier than a dremel with a flex shaft and a few tungsten carbide grinding burs. Oh yeah, if any of you have one of these 1127 series saws and have not modified the muffler, you are missing out. They are very choked up from the factory. They are easy to open up and they don't have to be as loud as this one is either.
No it hasn't made its way to Tennessee yet but hopefully it happens this winter. I did use it a heck of a lot this past weekend though . You did a great job putting that saw together and the cleanup looks great! You planning on keeping it or selling it?