What are some common and inexpensive mods on Husky saws, 385xp, 372xp, 335xpt and 338xpt? I love how all of my saws cut but you can never have too much power!
Mods
- Thread starter Hard_Corps
- Start date
- Location
- S.E. Wisconsin
The three ways I know of are: improving the cutting system, increasing the motor output, and improving cutting technique.
The first thing you need to do any of these is get a nice straight log and a helper with a stop watch. Start slicing cookies, have your timer shout out times as you cut. Try different cutting speeds, and techniques. Remember what works, and practice. You should be able to get 20% or so faster cuts than when you started, with no saw mods.
The next best way is to learn how to sharpen the chain. You should be able to get 10 or 20% over a new chain, just by hand filing it. If your not using square ground chain, that'll get you another 10% or so. Running a bigger sprocket can get you some more too, test every step on your log.
The best way to get more power from your saw is to open up the muffler, perhaps 15 to 50%. You'll need to richen up the highspeed jet, so make sure you have one before you start, otherwise you'll run too lean. If not you'll need to change jets, change carbs, or be real handy with a drill, to get the richer setting you'll need. Some carbs, (like those little huskys), with adjustable high speed jets barely richen up enough even if you open the jets all the way.
The idea is just make the outlet hole on the exaust as big as you can so the screen still covers the hole. Typically this is about 1.25 times the size of the exaust port at the piston. Just remove the exaust, remove the screen, use a round file or dremel type tool to enlarge the hole, reassemble, re-tune the carb, and go be amazed at the new power!
If your screen set-up is goofy like the ms200, just get a bigger screen and figure how to mount it. As discussed in other threads, the screen fundamentally reduces the size of the outlet hole, but is needed to keep crap out of the motor. So if removing the screen increases power, make the hole bigger and add a bigger screen. Although just running without a screen will work for those guys who don't much care about their tools. I have a couple older saws where the screens fell off, and I'm too lazy to replace them. On a newer saw or saws I personally own, the screens get checked regularly.
Sorry to have rambled on so, it's a big subject.
The first thing you need to do any of these is get a nice straight log and a helper with a stop watch. Start slicing cookies, have your timer shout out times as you cut. Try different cutting speeds, and techniques. Remember what works, and practice. You should be able to get 20% or so faster cuts than when you started, with no saw mods.
The next best way is to learn how to sharpen the chain. You should be able to get 10 or 20% over a new chain, just by hand filing it. If your not using square ground chain, that'll get you another 10% or so. Running a bigger sprocket can get you some more too, test every step on your log.
The best way to get more power from your saw is to open up the muffler, perhaps 15 to 50%. You'll need to richen up the highspeed jet, so make sure you have one before you start, otherwise you'll run too lean. If not you'll need to change jets, change carbs, or be real handy with a drill, to get the richer setting you'll need. Some carbs, (like those little huskys), with adjustable high speed jets barely richen up enough even if you open the jets all the way.
The idea is just make the outlet hole on the exaust as big as you can so the screen still covers the hole. Typically this is about 1.25 times the size of the exaust port at the piston. Just remove the exaust, remove the screen, use a round file or dremel type tool to enlarge the hole, reassemble, re-tune the carb, and go be amazed at the new power!
If your screen set-up is goofy like the ms200, just get a bigger screen and figure how to mount it. As discussed in other threads, the screen fundamentally reduces the size of the outlet hole, but is needed to keep crap out of the motor. So if removing the screen increases power, make the hole bigger and add a bigger screen. Although just running without a screen will work for those guys who don't much care about their tools. I have a couple older saws where the screens fell off, and I'm too lazy to replace them. On a newer saw or saws I personally own, the screens get checked regularly.
Sorry to have rambled on so, it's a big subject.
Exactly what I was looking for! Thanks Mike.
- Location
- S.E. Wisconsin
You're welcome, glad to help. Let me know if you if you have more specific questions. If I can't answer them, there are others here that can (or at least know where to get the answers).
- Location
- S.E. Wisconsin
Yeah, and we can make fun of you for running a saw with such dull cutters! /forum/images/graemlins/grin.gif
Instead of apologizing for large images, how about resizing them? It's not rocket science...
I've heard that a Dan Henry cylinder swap-out on a saw will also increase horsepower.
Like Mike hinted, sharpening your chain will undo all the undoing of the Walkers muffler job you're doing by running that chain. Personally, I'm not a fan in the least of open exhaust outlets and I've even heard they are not allowed on some government property.
I've heard that a Dan Henry cylinder swap-out on a saw will also increase horsepower.
Like Mike hinted, sharpening your chain will undo all the undoing of the Walkers muffler job you're doing by running that chain. Personally, I'm not a fan in the least of open exhaust outlets and I've even heard they are not allowed on some government property.
Eric what's the muffler go for?
Norm_Hall
New member
- Location
- Wauconda, (Chicago),IL,USA
I'd be interested too$$$
Norm_Hall
New member
- Location
- Wauconda, (Chicago),IL,USA
Glen, Got to the site. Thank you.
- Location
- S.E. Wisconsin
Once you get the new muffler and look at how they made it, you'll undestand how simple it is. They just open it up so more exaust can flow out.
A restricted exaust reduces the amount of unburned gas from flowing out the exaust.
On a 2 stroke, as the piston comes down, the burned gas shoots out the exaust port and unburned fuel enters the other side of the cylinder. A small exaust opening slows down that flow across the top of the piston, so little unburned gas gets out, which reduces emissions of unburned gas. The down side is that when the piston comes back up, there is still burned exaust in the cylinder, which means there is less fuel mix in there.
Opening the muffler allows a free flow of incoming fuel to the cylinder, so almost all the exaust is expelled. The down side here is unburned gas is flowing past the cylinder and going into the exaust. This means more power and cooler running, but lower fuel economy, extra pollution, and a louder saw.
If you have an older saw, you won't get much, if anything, from opening the exaust. Not being faced with emission laws, they just built the exaust as efficiently as possible. One easy way to fix up new saws is to buy an exaust from the same model saw from an earlier production year.
Some new saws, like husky's replacement for the 372, are introducing a strato charged engine. This works by squirting a blast of air inbetween the burned exaust and incoming fuel. The air is brought up by two pipes from the airbox and into the engine, just like the fuel mix, through ports in the cylinder.
Strato charged engines will also react differently to muffler mods.
A restricted exaust reduces the amount of unburned gas from flowing out the exaust.
On a 2 stroke, as the piston comes down, the burned gas shoots out the exaust port and unburned fuel enters the other side of the cylinder. A small exaust opening slows down that flow across the top of the piston, so little unburned gas gets out, which reduces emissions of unburned gas. The down side is that when the piston comes back up, there is still burned exaust in the cylinder, which means there is less fuel mix in there.
Opening the muffler allows a free flow of incoming fuel to the cylinder, so almost all the exaust is expelled. The down side here is unburned gas is flowing past the cylinder and going into the exaust. This means more power and cooler running, but lower fuel economy, extra pollution, and a louder saw.
If you have an older saw, you won't get much, if anything, from opening the exaust. Not being faced with emission laws, they just built the exaust as efficiently as possible. One easy way to fix up new saws is to buy an exaust from the same model saw from an earlier production year.
Some new saws, like husky's replacement for the 372, are introducing a strato charged engine. This works by squirting a blast of air inbetween the burned exaust and incoming fuel. The air is brought up by two pipes from the airbox and into the engine, just like the fuel mix, through ports in the cylinder.
Strato charged engines will also react differently to muffler mods.
- Location
- Winthrop, WA
I've done exhaust mods on my saws, both personal and work, with good results. I like how Stihl has ported front plates for 044's/046's from the old 046 mags, and also for 066's from the 066 mags. Easy way to get more exhaust flow. The question I have is can you go too big? Judging by that walker job, I've never opened anything up too big, but I've heard people (mostly people who knew even less than I do) say you can. Wondering if there's any truth to that.
As to not being able to use modified exhausts on federal lands, I have never heard that. I work for the Forest Service (don't quote me, I'm just a knuckle-dragging sawyer on a fire handcrew) and we file out almost all of our saws. Our district doesn't fully endorse it, but some of the districts around us put the 046 mag plates on all their saws, or have secondary ports brazed onto the left hand side of the muffler. You cannot, however, run an un-arrested muffler on federal land. So if you straight up drill a hole through your muffler without putting in a screen, you could get busted.
As to not being able to use modified exhausts on federal lands, I have never heard that. I work for the Forest Service (don't quote me, I'm just a knuckle-dragging sawyer on a fire handcrew) and we file out almost all of our saws. Our district doesn't fully endorse it, but some of the districts around us put the 046 mag plates on all their saws, or have secondary ports brazed onto the left hand side of the muffler. You cannot, however, run an un-arrested muffler on federal land. So if you straight up drill a hole through your muffler without putting in a screen, you could get busted.
- Location
- S.E. Wisconsin
[ QUOTE ]
The question I have is can you go too big? Judging by that walker job, I've never opened anything up too big, but I've heard people (mostly people who knew even less than I do) say you can. Wondering if there's any truth to that.
[/ QUOTE ]
As you get bigger than the optimal exaust pipe opening size, the gains will drop off, but as your opening continues to get bigger, fuel consumption, noise, and unburned fuel emmisions, all increase. At some point, a lack of back pressure may also cause a loss in power.
Remember, the fuel air mixture is leaned out by increasing the size of the exaust opening. If you make that opening bigger, you need to adjust the carb richer. This is done with a tachometer and a screw driver. Simply adjust the high speed jet, with the saw running, until the wide open throttle (WOT) RPMs are at the factory recommended maximum RPMs.
Plastic limiter caps can be troublesome to remove, but not that big a deal.
You can also get into trouble with some saws that don't have an adjustable high speed jet (HSJ). These typically have different size jets you have to buy and tear the carb apart to install.
Another problem is some new carbs don't have much adjustment, even with the HSJ all the way open, it may not flow enough fuel to match an aggressive exaust opening.
I recommend richening up the carb, then opening up the exaust incrementally until you achieve the proper RPMs. It's easier to lean the carb back out than to put metal back on the exaust. /forum/images/graemlins/grin.gif
The question I have is can you go too big? Judging by that walker job, I've never opened anything up too big, but I've heard people (mostly people who knew even less than I do) say you can. Wondering if there's any truth to that.
[/ QUOTE ]
As you get bigger than the optimal exaust pipe opening size, the gains will drop off, but as your opening continues to get bigger, fuel consumption, noise, and unburned fuel emmisions, all increase. At some point, a lack of back pressure may also cause a loss in power.
Remember, the fuel air mixture is leaned out by increasing the size of the exaust opening. If you make that opening bigger, you need to adjust the carb richer. This is done with a tachometer and a screw driver. Simply adjust the high speed jet, with the saw running, until the wide open throttle (WOT) RPMs are at the factory recommended maximum RPMs.
Plastic limiter caps can be troublesome to remove, but not that big a deal.
You can also get into trouble with some saws that don't have an adjustable high speed jet (HSJ). These typically have different size jets you have to buy and tear the carb apart to install.
Another problem is some new carbs don't have much adjustment, even with the HSJ all the way open, it may not flow enough fuel to match an aggressive exaust opening.
I recommend richening up the carb, then opening up the exaust incrementally until you achieve the proper RPMs. It's easier to lean the carb back out than to put metal back on the exaust. /forum/images/graemlins/grin.gif
- Location
- Hotaka, Japan
Encouraged by what I read here, I opened up the muffler on my old Stihl 038AV. It had a big baffle plate inside that the exhaust could only pass through two narrow slits in, before finally exiting out the small side port on the outside of the muffler. Talk about a repressed muffler! After taking out the baffle, I drilled a 3/4" hole in the front and secured a screen over it with some nuts and bolts. Now the muffler is breathing healthy with a straight shot out from the cylinder, and I must be getting like a quarter more power out of the tool. I also notice that the neighbors are now closing their windows when I'm working on the firewood stash. I gave the high speed screw an eighth turn open. I think I can line up a tach. Can anyone advise what the high speed rpm setting is on this saw, and is the adjustment done with the chain off? Newbie here, thanks for the help.
Regards,
Jay
Regards,
Jay
The only way to be sure you've gained something more than noise is with a closely-controlled timed-cut comparison (too late, right?). I believe the saws which benefit most from opening the muffler are the EPA saws. The 038 isn't really new enough for that, is it? Generally speaking, I wouldn't mess with the muffler on a saw which came from the factory with two non-limited carb-jet screws.
It would be safer to make the adjustment with the chain off, safer both for the act and the resultant setting. It wouldn't necessarily provide the optimal setting but it certainly wouldn't be too lean, which is really your greatest concern. The best setting is the one which gives you the fastest cutting time.
I don't have an 038 manual, but the 044 says the max. RPM is 13,500 with bar and chain. The 038 would likely be a bit lower than that. Naturally, the bar/chain length would be a factor, as would the atmospheric conditions, so this really isn't a "set and forget" thing.
Want to get anally technical? Find the fastest cut time setting which doesn't exceed max. recommended RPM (I'll guess 12,800), note what the actual no-load RPM is on your tach, and just set it to that in the future.
The Chainsaw Collector's Corner lists 13,500 no-load w/ bar/chain for the 72cc 038.
It would be safer to make the adjustment with the chain off, safer both for the act and the resultant setting. It wouldn't necessarily provide the optimal setting but it certainly wouldn't be too lean, which is really your greatest concern. The best setting is the one which gives you the fastest cutting time.
I don't have an 038 manual, but the 044 says the max. RPM is 13,500 with bar and chain. The 038 would likely be a bit lower than that. Naturally, the bar/chain length would be a factor, as would the atmospheric conditions, so this really isn't a "set and forget" thing.
Want to get anally technical? Find the fastest cut time setting which doesn't exceed max. recommended RPM (I'll guess 12,800), note what the actual no-load RPM is on your tach, and just set it to that in the future.
The Chainsaw Collector's Corner lists 13,500 no-load w/ bar/chain for the 72cc 038.
Not a dispute but rather an observation.The Stihl 038,038 super and 038 mag are all listed at 12,000 rpm ,with bar and chain as per Stihl micro fiche set.
As far as gaining rpms by hogging out a muffler,it isn't neccesary at all.You are gaining power by simpley improving the flow through the saw.
I've done a bit of muffler work on my 038 and yes in fact it does enhance the performance a bit.It's a bit more noisey but not that much.
As far as gaining rpms by hogging out a muffler,it isn't neccesary at all.You are gaining power by simpley improving the flow through the saw.
I've done a bit of muffler work on my 038 and yes in fact it does enhance the performance a bit.It's a bit more noisey but not that much.
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