Modded Saws

shaggs · 24th November 2007, 12:20 AM

You never know till you try Kevlar! Show us some build pics if you can.
BTW do you notice any difference between your 036 and 38? cheers

kevlar · 24th November 2007, 11:32 AM

Quote:

Originally Posted by shaggs

You never know till you try Kevlar! Show us some build pics if you can.
BTW do you notice any difference between your 036 and 38? cheers

Between the 036 and the 038 mag-big time!! My 038 mag would run over stock 440's.

kevlar · 24th November 2007, 11:37 AM

as far as build pics I don't really have any,I sneak a grind in here and a weld in there and a shave here all when the boss ain't looking-he thinks it's a customer saw anyways.Maybe some assembly pics when I bring it home tonite!just for you.

newguy18 · 24th November 2007, 12:35 PM

Sounds good i think when I rebuild my 141 I'm gonna mod the muffler by removing all the cat crap and maybe a little bit bigger cylinder.

Therrin · 24th November 2007, 07:15 PM

You could try just telling the cat not to crap in your muffler.

Ekka · 24th November 2007, 09:49 PM

What does 0.030" off the bottom of a piston do exactly?

Also, why off the top, wouldn't that decrease compression?

kevlar · 25th November 2007, 01:44 AM

Quote:

Originally Posted by Ekka

What does 0.030" off the bottom of a piston do exactly?

Also, why off the top, wouldn't that decrease compression?

Off the top compenates for the removal of the base gasket,otherwise it may strike the top or will not release the exhaust charge quickley enough-which brings us to the bottom of the piston skirts that allow the intake charge to spill into the crankcase the shorter the skirt the quicker the charge -WHITHIN REASON! that is why I use 30 thou I know I could go more but...

ScottWojo · 5th December 2007, 06:11 PM

Quote:

Originally Posted by kevlar

Off the top compenates for the removal of the base gasket,otherwise it may strike the top or will not release the exhaust charge quickley enough-which brings us to the bottom of the piston skirts that allow the intake charge to spill into the crankcase the shorter the skirt the quicker the charge -WHITHIN REASON! that is why I use 30 thou I know I could go more but...

Ok, I am talking above my paygrade here...

You can adjust the squish clearance by sanding the base of the cylinder and dropping the cylinder closer to the top of the piston. This increases compression and power. Some of the guys will also adjust the port timing to compensate. You can also widen the exhaust port and polish the walls.

You can measure the squish using some lead solder into the spark plug hole. Usually you do not want to go less than .015" on a work saw. But you measure the solder once you have squished it by running the piston into it. Then you can adjust the cylinder from there.

On the piston skirt, you can cut the skirt on the intake side only. By cutting a good chunk out of that you will make the saw run better. Not sure why, but it works.

Of course you need to match the muffler to the worked over exhaust port and dual port the saw as well.

If anyone wants to talk to smarter people than me, send me an email.

Scott.

kevlar · 5th December 2007, 06:33 PM

Quote:

Originally Posted by ScottWojo

Ok, I am talking above my paygrade here...

You can adjust the squish clearance by sanding the base of the cylinder and dropping the cylinder closer to the top of the piston. This increases compression and power. Some of the guys will also adjust the port timing to compensate. You can also widen the exhaust port and polish the walls.

You can measure the squish using some lead solder into the spark plug hole. Usually you do not want to go less than .015" on a work saw. But you measure the solder once you have squished it by running the piston into it. Then you can adjust the cylinder from there.

On the piston skirt, you can cut the skirt on the intake side only. By cutting a good chunk out of that you will make the saw run better. Not sure why, but it works.

Of course you need to match the muffler to the worked over exhaust port and dual port the saw as well.

If anyone wants to talk to smarter people than me, send me an email.

Scott.

I tried doing only the intake side but it seems the piston becomes unstable and rocks? by taking material off both sides seems to stay balanced and works better(for me anyways.)

ScottWojo · 5th December 2007, 06:39 PM

Quote:

Originally Posted by kevlar

I tried doing only the intake side but it seems the piston becomes unstable and rocks? by taking material off both sides seems to stay balanced and works better(for me anyways.)

Wow, thats odd. My 066 is woods ported and is like that. Not one bit of problem. Like I said, I am only a muffler guy. The engine builder is a special person. I hang out on another racing site where you would swear the guys were engineers.

Scott.

windthrown · 5th December 2007, 11:09 PM

Back pressure is needed in 2-stroke engines to keep them running better. Unlike a 4-stroke where you want to get rid of all the burned gasses in the combustion chamber before a fresh intake stroke of more gas and air mixed, the 2-stroke combustion is pushing the exhaust out at the same time it is pumping gas/air mix into the chamber for the next stroke. If you allow too much air flow, you will get raw gas/air pumping out the exhaust port before the piston closes the port and burns it. You do not want that to happen. So you need a nice ballance of back pressure from the exhaust system to keep the gas/air mix inside the combustion chamber.

The way to do that with an expansion chamber in a hot saw setup is to have an open pipe that is shaped right. What happens is the hot exhaust gasses escape from the piston at high pressure. This creates an exhaust pressure wave, which expands in the exhaust pipe until they hit the far side of the pipe where it narrows down in size. Then the pressure wave bounces back toward the exhaust port of the saw, and that in turn pushes the escaping unburned air/gas mix back in through the exhaust port before it closes.

I used to race 2-stroke dirt bikes when I was a lot younger. Some exhaust flow is good, but a completely open exhaust in a 2-stoke engine is not. I think that is a lot of cases people open up their chainsaw mufflers too much when they modify them. I opened up my 290 to only about 2.5x the size of the factory openings on the muffler (which are really small). Not a whole lot louder, but enough to get a lot more air flow, without too much air flow.

shaggs · 26th December 2007, 03:07 AM

ANYONE DONE ANY GOOD MODS LATLEY????

windthrown · 1st January 2008, 01:46 AM

Yah... I muffler modded my baby Stihl 210 with a screwdriver. Opened up the muffler tangs with a large flat screwdriver and tweeked the carb H setting to richen it up a bit. Then tweeked the L and LA settings, and she seems to run better now. Poor man's mod. Cost me nothing, no parts had to be removed, and it took about 10 minutes. Only tools required are a large flat head screwdriver and the tiny orange Stihl screwdriver. Of course I had removed the limiter tab a while back on the H side of the carb.

A while back I also opened up my 290 by making the small muffler holes larger with a chain grinding tool. Only have to take off the little cover on the muffler and grind open the holes, maybe 2 times larger than they were. Then I ground a larger hole in the exit port on the muffler cover plate. Then I cut the limiter tang on the H side of the carb, and opened it up to about 1-1/8 turn. Also reset the L side and idle, and it has a lot more zip.

I gotta muffler mod my 361 now too.

newguy18 · 1st January 2008, 07:46 AM

A little off topic but I changed the oil and dropped my pil pan last weekend and I couldn't get the oil filter off and I don't use an oil filter wrench so I stabbed through it with a screw driver and twisted and off it came.

poor mans oil filter wrench.

Tree Machine · 1st January 2008, 09:57 AM

Quote:

Originally Posted by shaggs

ANYONE DONE ANY GOOD MODS LATLEY????

Here's a mod from a couple different angles.

First, the .325 sprocket was removed and a 3/8, 8-pin sprocket put on.
The 16" .325 .050 bar was offed and replaced by a 14" hard nose titanium bar so we can run
the 3/8" thinner kerf chain like on the top-handle saws.

The muffler mod my guy put in is recessed back in, hard to see, but seeing it really isn't the point.

This new saw is the same setup I've been running for 2 years on my current aerial partner. It's my personal preference for
a climbing saw, you can get a lot of cutting done on a single tank of gas.

shaggs · 1st January 2008, 01:27 PM

TM
Nice to see you cloour code the bar and saw!!!

The port doesn't effect the handle??? Maybe the angle of the photo.

24th November 2007, 12:20 AM	#26 (permalink)
shaggs Afterburner is shakin' Join Date: May 2007 Location: sydney Posts: 459	Re: Modded Saws You never know till you try Kevlar! Show us some build pics if you can. BTW do you notice any difference between your 036 and 38? cheers

24th November 2007, 11:37 AM	#28 (permalink)
kevlar Gettin' motoring Join Date: Nov 2007 Location: British Columbia Posts: 47	Re: Modded Saws as far as build pics I don't really have any,I sneak a grind in here and a weld in there and a shave here all when the boss ain't looking-he thinks it's a customer saw anyways.Maybe some assembly pics when I bring it home tonite!just for you. __________________ Got Wood!! olympyk 264 deluxe,999.jonsered 66e.huskvarna 394. stihl 026pro,036pro,038 mag,045,046,460,056mag,066,075.homelite super xl and xl12. pioneer 600a,maculloch d36and pro mac1000.whew! What out for the boy he's crazy!! Last edited by kevlar : 24th November 2007 at 01:24 PM.

24th November 2007, 12:35 PM	#29 (permalink)
newguy18 Tree World Icon Join Date: Jun 2007 Location: Live Oak Florida home of the crapiest trees you will ever see. Posts: 2,188	Re: Modded Saws Sounds good i think when I rebuild my 141 I'm gonna mod the muffler by removing all the cat crap and maybe a little bit bigger cylinder. __________________ Have your say join us today. http://www.youtube.com/watch?v=Xzkd_m4ivmc http://www.youtube.com/watch?v=Xzfzb...eature=related http://www.youtube.com/watch?v=x-OqK...eature=related

24th November 2007, 07:15 PM	#30 (permalink)
Therrin The Tree World Bandit Join Date: Oct 2007 Location: Lancaster, Ca Posts: 1,112	Re: Modded Saws You could try just telling the cat not to crap in your muffler. __________________ Ken Fessia I.T.S.A. Tree Service (661) 916-4703

24th November 2007, 09:49 PM	#31 (permalink)
Ekka Eric Frei Administrator - Brisbane L5 (Dip) Hort Cert III Arb + some Join Date: Jan 2007 Location: Brisbane Posts: 5,669	Re: Modded Saws What does 0.030" off the bottom of a piston do exactly? Also, why off the top, wouldn't that decrease compression? __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping Brisbane Tree Care, Consultations and Arborist Reports Forum Sponsors

5th December 2007, 11:09 PM	#36 (permalink)
windthrown Fly'n Join Date: Dec 2007 Location: Pacific Northwest USA Posts: 125	Re: Modded Saws Back pressure is needed in 2-stroke engines to keep them running better. Unlike a 4-stroke where you want to get rid of all the burned gasses in the combustion chamber before a fresh intake stroke of more gas and air mixed, the 2-stroke combustion is pushing the exhaust out at the same time it is pumping gas/air mix into the chamber for the next stroke. If you allow too much air flow, you will get raw gas/air pumping out the exhaust port before the piston closes the port and burns it. You do not want that to happen. So you need a nice ballance of back pressure from the exhaust system to keep the gas/air mix inside the combustion chamber. The way to do that with an expansion chamber in a hot saw setup is to have an open pipe that is shaped right. What happens is the hot exhaust gasses escape from the piston at high pressure. This creates an exhaust pressure wave, which expands in the exhaust pipe until they hit the far side of the pipe where it narrows down in size. Then the pressure wave bounces back toward the exhaust port of the saw, and that in turn pushes the escaping unburned air/gas mix back in through the exhaust port before it closes. I used to race 2-stroke dirt bikes when I was a lot younger. Some exhaust flow is good, but a completely open exhaust in a 2-stoke engine is not. I think that is a lot of cases people open up their chainsaw mufflers too much when they modify them. I opened up my 290 to only about 2.5x the size of the factory openings on the muffler (which are really small). Not a whole lot louder, but enough to get a lot more air flow, without too much air flow. __________________ So few saws, so many trees... Stihls: 210/250-/025/290/361/FS85 Echo: CS-3000, Olympyk & Mac doorstops

26th December 2007, 03:07 AM	#37 (permalink)
shaggs Afterburner is shakin' Join Date: May 2007 Location: sydney Posts: 459	Re: Modded Saws ANYONE DONE ANY GOOD MODS LATLEY????

1st January 2008, 01:46 AM	#38 (permalink)
windthrown Fly'n Join Date: Dec 2007 Location: Pacific Northwest USA Posts: 125	Re: Modded Saws Yah... I muffler modded my baby Stihl 210 with a screwdriver. Opened up the muffler tangs with a large flat screwdriver and tweeked the carb H setting to richen it up a bit. Then tweeked the L and LA settings, and she seems to run better now. Poor man's mod. Cost me nothing, no parts had to be removed, and it took about 10 minutes. Only tools required are a large flat head screwdriver and the tiny orange Stihl screwdriver. Of course I had removed the limiter tab a while back on the H side of the carb. A while back I also opened up my 290 by making the small muffler holes larger with a chain grinding tool. Only have to take off the little cover on the muffler and grind open the holes, maybe 2 times larger than they were. Then I ground a larger hole in the exit port on the muffler cover plate. Then I cut the limiter tang on the H side of the carb, and opened it up to about 1-1/8 turn. Also reset the L side and idle, and it has a lot more zip. I gotta muffler mod my 361 now too. __________________ So few saws, so many trees... Stihls: 210/250-/025/290/361/FS85 Echo: CS-3000, Olympyk & Mac doorstops

1st January 2008, 07:46 AM	#39 (permalink)
newguy18 Tree World Icon Join Date: Jun 2007 Location: Live Oak Florida home of the crapiest trees you will ever see. Posts: 2,188	Re: Modded Saws A little off topic but I changed the oil and dropped my pil pan last weekend and I couldn't get the oil filter off and I don't use an oil filter wrench so I stabbed through it with a screw driver and twisted and off it came. poor mans oil filter wrench. __________________ Have your say join us today. http://www.youtube.com/watch?v=Xzkd_m4ivmc http://www.youtube.com/watch?v=Xzfzb...eature=related http://www.youtube.com/watch?v=x-OqK...eature=related

1st January 2008, 01:27 PM	#41 (permalink)
shaggs Afterburner is shakin' Join Date: May 2007 Location: sydney Posts: 459	Re: Modded Saws TM Nice to see you cloour code the bar and saw!!! The port doesn't effect the handle??? Maybe the angle of the photo.

1st January 2008, 01:31 PM	#42 (permalink)
shaggs Afterburner is shakin' Join Date: May 2007 Location: sydney Posts: 459	Re: Modded Saws