New to forum...just bought MS390...

[fishhuntcutwood]

Something simple like intake and exhaust mods?

Do a search on the site for that. I don't know that 390 muffler mods have been discussed, but I know that 029 mods have, and they'll be the same, so read up on those.

Jeff

 

[Diesel JD]

Hey guys, here's what I did. I went back to the Stihl dealer and switched out the 28" bar for a 25". Man......what a difference. It may not be as fast as it would be with a 20 or 18 inch bar, but with that I really haven't gained much over the 025, have I? Anyways, the 28" was WAY too much bar, and the 25 works great in what I normally cut, no bogging. Had fun with it tonight, ran it until it was out of fuel. I'd still be interested in the muffler mod. Thanks,
J.D.

 

[computeruser]

Sounds like you made the right choice - no good comes of running too big a bar. I ran a 20" on my 290 for years, and it was alright. Now I'm running a 20" bar on a Dolmar 7900 (79cc, 6.3hp), and I wonder how I ever got anything done with the 290. Apart from top-handle saws, I see no reason to ever go back. The 290 is a backup/cut-out saw now.

I think if you open up the exhaust some, you will be very pleased with your saw. The 290/310/390 saws are solid saws and mine has been utterly reliable, they are just choked up. Open up the exhaust and you'll be pleased, from everything I've heard.

 

[Diesel JD]

I've been reading some of these threads the guys posted, is drilling the muffler how this is done? Or must it actually be pulled off and gutted? Is it true that the fuel mixture at the carb needs to be richened up some to avoid trouble if the muffler is opened? Thanks,
J.D.

 

[geofore]

Diesel JD, I can tell your on your way to a case of Sawitius. There is no point in trying to justify the next purchase, it will over take you in no time. In the mean time learn to put a sharp edge on the chain, touch it up every other tank of fuel or more often and it'll keep the chips flying. Yes, you should richen it up a bit if you drill the muffler, not a lot, some.

 

[fishhuntcutwood]

I've been reading some of these threads the guys posted, is drilling the muffler how this is done? Or must it actually be pulled off and gutted? Is it true that the fuel mixture at the carb needs to be richened up some to avoid trouble if the muffler is opened? Thanks,
J.D.

I'd take it off the saw. It'll make it easier to work on, and you'll be able to clean out the metal shavings from drilling or cutting, and keep them out of the cylinder. You can just drill it, or you can gut it. Different mufflers are done differently by different folks. Don't get too aggressive with it, or you'll not gain as much power as you have just plain noise. Like geofore said, just a little. You can always take more out, but you can't put it back in.

And again, yes you'll have to richen it up. You'll be allowing more air through, which is a leaner condition. Too lean is bad. Too rich is bad too, but too lean is worse.

Jeff