Yep, that's what several saw builders use, they mostly weld them on from what I've seen. The one I had didn't like the screen though, broke it off and spat it out.
Ian
Ian
Hey Junior, welcome to AS. Great 1st post. Yes, 4 Paws does make some excellent tutorial threads. Does your 372XP have a limited ignition module? These make tuning more difficult and you can damage your saw if you lean it out too much. The limited modules are blue in color. It will also have the maximum RPM rating engraved on the side of the module. The unlimited modules are black in color. The black module is the one that you want. Another important tool is a tachometer so that you can accurately set the carb. Seeing numbers on the tach is safer than trusting your ears, especially if you are new at this or if your hearing ain't what it used to be.
My dual port cover (pn 1122 140 0800) came in at my Stihl dealer but not my gasket so I had to use high temp RTV sealer for now to get my saw running to cut all these trees the storm has blown down. I'll go back and put the gasket in there when I get it.
I tuned the carb to the new exhaust and cut some wood. WOW, this saw gives me a virtual adrenaline overdose.
The blue module obviously prevents the saw from turning over 13,500 RPM's. (The leaner the mixture the faster the saw turns.) It does not prevent you from leaning out the fuel/air mixture to the point that you damage the piston and/or the cylinder. The saw simply will not spin faster than the cut out point built into the module, regardless of how lean the "H" screw is turned. Some folks adjust their carbs so that the saw is running approximately 200 RPM's below the cut-off point. That way you know that you are safe. The black coil will not mask an improperly adjusted carb. You lean out a saw with a black module and it will scream. A tach is a handy tool to have and it is even more critical to use one when setting up a saw with a limited ignition module.
Thanks Nailsbeats.That's some sweet work man. I just finnished my second 660's muffler mod. I just open the side vent all the way to that slit and leave the stock front muffler cover on. I also chop the front of that cage off, I should plasma them totally off like you did. Longterm, I probably will. Again, nice job, looks really nice. Really makes em' cut don't it.
Thanks Nailsbeats.
Note that I only used the plasma cutter to separate the cage into sections that would enable those sections to flex on the factory spot welds. Then the sections came loose from the factory spot welds with very little effort and absolutely no metal damage to the muffler housing. The Plasma arc will blow a hole in the muffler housing very easily if it gets close to it. Don't try to cut the spot welds that are holding the cage to the housing.
Also, if you do completely remove the cage, this will leave only the thin metal that the housing is made of to support the entire muffler assembly where it bolts to the cylinder. This would be a weak point and over time will likely break due to vibration, metal fatigue ect. That's why I welded the stainless plate in place of the cage - for support. Are you planning to weld in a support plate also on your project?
Looking back, I think my first mod of just cutting the front out of that cage and also opening up the outlet supplied plenty of flow, and I do not believe completely removing the cage gave the saw any more power. Sure, with the cage removed there's no doubt about minimal exhaust restriction, but I think there's plenty of flow for the stock 660 with the cage in place. The main restriction that causes power loss is the small final exhaust output opening. In my opinion, with that area opened up, you should see all the power increase your going to see with a muffler mod on a stock saw. At the time I modded that muffler, I had plans to eventually do some extensive mods to the motor.didn't want to find out I needed the support, so I left it. I don't suspect it is impeding flow much.
The muffler just came out of the oven from being coated with exhaust paint: