"Opening" up an 066

[thompson1600]

I have been reading through the archives and hear talk of the Dual Port 066 being a little more stout than the newer decompression valve 066. Some threads also mentioned opening up the newer decompression valve 066 to get it more power.

What exactly is meant by "opening it up"? How exactly do you do that (or best left for the tech's)?

Thanks

Tom

 

[HUSKYMAN]

The only difference is the dual port refers to the dual port magnum muffler that came with the old 066's. You can do the same to yours, just cut two holes in the muffler and braze a pair of 5/8" ports on and voila

 

[don]

Best way to open it up

Is there anyone who sells a "tuned" pipe for a 066 or are they all custom? Would this be the most cost effective upgrade to get a saw more horse power and longer life?

 

[rbtree]

A tuned pipe is for race saws only, usually 16-24 inches long, costs 300-600 to have built.

Muffler mods, to stock ones, can add over 25% power gains, according to the saw builders.

I have 7 woods built saws, now I want a race ready one, pipe and all. The Clearwater Revival got me hooked.

 

[kdhotsaw]

066 stihl muffler

Hello Tom (Thompson 1600),
The muffler work that we do to the 066 muffler to increase the power is as follows; go inside and cut the end out of the stainless steel perforated box at the exhaust inlet, match the exhaust entry and gasket to the barrel opening, and on the 066 go to your local stihl dealer and buy the ported cover for the 066 magnum muffler. its 31.00 dollars and has a screen and deflector over the port
this will add 15-20 % to the power level. you can also cut a port in your existing cover, if you do make the port 1 1/2 long by 7/16 tall
ken
kdhotsaw@hotmail

 

[kdhotsaw]

racing pipe

hello don,
you could put a expansion chamber on a stock 066. you would see a 45-50 % power increase but they are big and cumbersome. if you didnt have the jetting in your carb right you could overheat the saw . we build pipes to the proper measurements for a saw engine. you need to know the exhaust duration in degrees and the rpm you are going to cut to determine the overall length of the pipe.we also convert yahama kts100 kart pipes to fit our saw motors. they operate at about the same rpm and exhaust duration as our saw motors so we can modify them easily. for a good running 066 woods saw i would concentrate on you muffler , porting and compression and squish band work.
ken
kdhotsaw@hotmail

 

[kdhotsaw]

expansion chambers

Hello Roger,
Yes, once you run a piped version and compare it to a muffled version of the same saw your hooked. I have a dyno test out of one of the motorcycle magazines that tested a stock 250 suzuki, it produced 42 h.p. with the pipe. they removed the pipe and ran it and it dyno'd 22 h.p. they then removed 10 mm from the header section of the pipe and ran it and it lost 2 h.p.. anyway we get 40-50 % more hp
There were some good running saws at clearwater, jon and mike rooply have some nice saws and if they are running uncle arts chain they are hard to beat. ol leroi lambert did alright with his 088 and my 084. anyway if you want a pipe for your 3120 let me know, it will make that 3120 get up and bark
ken
p.s. enclosed a photo of one of my piped 3120's

 

[Gypo Logger]

Hi Dad, lil leroy here, what would the neighbours think if I went loggin with that piped 3120? Would Uncle Art be annoyed with me if I made felling cuts with the chains I got from him?
Anyway Ken your 3120 looks meaner than a junkyard dog.
John

 

[Weatherby]

I know this doesnt really pertain to this thread, but I wonder how fast that piped 3120 would go through that buffalo that someone posted awhile ago. I'd like to see that.

 

[WOLF_RIVER_MIKE]

Weatherby, I'm sure one of the mathmaticians on the list could probably/want to? figure that out. I know one thing, it wouldn't be as fast as that little 270 of mine.

 

[Dennis]

Weatherby...lol..that was my buffalo...and well...I am not sure that it would have fit up inside the chest cavity the way the little Jonny did....

 

[Gypo Logger]

Hey Dennis, the only trouble with that lil Jony Red and quartering that cadaver, is your not going to get the required fountain of beef dust emerging from the side cover. Why dont you try a real saw, such as my JD066 which cranks out 8 hp and will make any Woodland Buffalo take a face plant off Pink Mountain.
Great White Hunter

 

[Sethro]

opening a 066

thompson1600
Here is a picture of my 044 with 5/8 inside dia.muffler ports. I used conduit.
be sure you remove all of the galvnived coating of the conduit before any welding!!! Seth

 

[don]

Nice mod nelsonfrye

Do you notice the increase in power? Did you put any screen mesh on those "pipes" to prevent anything getting inside?

 

[don]

So why can't you just drill a couple holes?

So why can't you just drill a couple of hole on the face of the muffler and put mesh over it? Drll the holes and a few screw holes next to them (for holding screws) get some mesh and bolt it on there?

 

[Sethro]

ports

Don
I have not put any screens in it yet,maybe today. Its fine to put the holes in the face plate of the muffler.Seth

 

[DaveCA]

Muffler Box

For milling and genaral firewood cuttin', I'm tryin' 'this' for now. It's load enough for me and makes the chips really fly.
I believe Ken Dunn said he removes the bottom of this box with the holes.

 

[DaveCA]

Drillit

Then I enlarged just 4 of the holes in the bottom of the box to 1/4 inch. This has to leave it more restrictive than KD's mod, likely to be quieter as well.

 

[DaveCA]

spent $$$

Then, since I enjoy spending money I bought this geuine Stihl part.

 

[DaveCA]

This cover is heavy. I think Don and KD said to put a hole in the original cover and add a screen, why not?