Silence is Golden......

[Lakeside53]

would sound cool when "compression braking", if they allow that in Tokyo

 

[Stu in Tokyo]

OK, if you have been reading along on little saga, then you know that I got told that someone complained about the big old Husky saw running for a long time. I guess I can see their point, as this is the middle of
Tokyo not some woods area. I'm at the woodlot on the my goodwill with the foreman of the Demo company, if me being there becomes a problem for him, I'm sure he will ask me to not be there.
I do not want that to happen, so I decided to quiet down the chainsaw, to do this I dug around and I found two old 2-smoke bike mufflers.

One is off my RMX, it is lighter weight, but is noisier, I did repack it just for this use

The second one is a stock muffler from a Honda CRM250.
I'll call this one the Black Hole, as it is black, heavy, and has a lot of sound deadening to it.

I did not want to butcher the original muffler, so I built a new muffler box.

Here is the space I'm working with, (I know, the saw is dirty)

I used a piece of tubing and a thick piece of steel that will tighten against the exhaust port.

 

[Stu in Tokyo]

Here it is welded up, I'm test fitting it.

Here the muffler box is all welded up, with the stub in place.

I'll use this stub to attach the muffler to the saw.

I bought this rubber muffler joint at the bike shop, this will make a good seal, and dampen some of the vibrations.

 

[Stu in Tokyo]

Just to give you an idea, this is what it will look like.

How does it work?

Well, I fired the saw up for about 30 seconds, and it was a lot quieter, in fact the intake is now the loud part!
I ran out of time today, I'll get back into the dungeon in the morning and hopefully get it all done.
I think it will be quiet, and that is good, I hope it will not be down on power, I'll have to warm the saw up and then tune it to get the best power out of it.
I got my carb parts, so I have to rebuild the carb as well.

Wish me luck!

 

[Lakeside53]

looks great, but is that a RUBBER connector to the muffler?

 

[Stu in Tokyo]

looks great, but is that a RUBBER connector to the muffler?

Yes, the stub on the muffler box is slightly larger than the muffler pipe, so the pipe fits into the stub. The rubber piece is a joint, or a seal.

It is for motorcycle mufflers, so it can withstand the heat.

Cheers!

 

[Lakeside53]

interesting, ... but it is awfully close to the cylinder outlet... no doubt you let us know if it survives!

 

[rmihalek]

Stu, I think with that much unsupported weight hanging off the cylinder, that you're going to crack some metal on the cylinder. Why not lay it down flat on top of the milling frame like a previous guy mentioned? That way you can direct the exhaust blast away from the neighbor's house and also have something to attach the far end of the baffle to so that the cylinder isn't supporting all the weight.

Also, when you're milling, isn't that silencer going to be right in front of your face?

 

[Stu in Tokyo]

I guess I'll find out if heat is a problem, this IS a work in progress, and if that seal does not cut it, then I'll just wrap the joint with muffler tape.

If I lay the muffler down, I'm afraid it will interfere with the milling, plus then it would be right next to my hand that I'm pushing on the mill with.

When milling, I stand behind the saw, the top of the saw, the sparkplug, is towards me, so the muffler is pointed straight up, which is also another good way to get rid of the noise.

The muffler on there now, the RMX aluminium one, is VERY light, I don't think it will be a problem, but I'll add a brace to it anyways.

The black hole muffler, yes, that would need support for sure, it is heavy.

I'll take more pics when I've got more done, I think it will be clearer then.

Cheers!

 

[timberwolf]

Something to think about,

Tuned length, Given your milling the saw maybe down around 10-11k, and the pipe temp will get rather high, I calculate your tuned length would be somewhere in the 775 mm (31 inch range). It looks as if you are quite a lot shorter than this. You do not want to go too long on the length, so that the reflected wave comes in after the port closes boosting engine temps, but if the pipe is too short the scavenging could be messed up and kill the low end torque needed for milling.

 

[Sprig]

Hm, what an honest bunch! (jk) (jk) I'm surprised no one has mentioned the old shakeblock stealing trick of running a length of hose into a pail of water, never did find the SOB's who were stealing our logs years ago but did find out how they were getting away with it after they forgot their hose and pail lol, left in a hurry I guess. I don't know how this would affect power etc, or if it is even safe for the saw (the slightly extra back pressure) but maybe someone else here has some (ahem *cough*) experience with this dampening method. It had to have been quiet as my workmate was camping not far away and heard nary a thing. Just a thought.

 

[Stu in Tokyo]

Something to think about,

Tuned length, Given your milling the saw maybe down around 10-11k, and the pipe temp will get rather high, I calculate your tuned length would be somewhere in the 775 mm (31 inch range). It looks as if you are quite a lot shorter than this.

TW, where are you measuring from?
The total length of the muffler is quite long, I'd say over 31 inches for sure, the length from the exhaust port to the beginning of the muffler (the aluminium part) is maybe 20" or so.

You do not want to go too long on the length, so that the reflected wave comes in after the port closes boosting engine temps, but if the pipe is too short the scavenging could be messed up and kill the low end torque needed for milling.

Having a motorcycle background, I'm aware of all of this, and how it works, but the only method I have for testing it is the old "Trial & Error", so I'll be doing just that and reporting back!

Cheers!

 

[Stu in Tokyo]

Hm, what an honest bunch! (jk) (jk) I'm surprised no one has mentioned the old shakeblock stealing trick of running a length of hose into a pail of water, never did find the SOB's who were stealing our logs years ago but did find out how they were getting away with it after they forgot their hose and pail lol, left in a hurry I guess. I don't know how this would affect power etc, or if it is even safe for the saw (the slightly extra back pressure) but maybe someone else here has some (ahem *cough*) experience with this dampening method. It had to have been quiet as my workmate was camping not far away and heard nary a thing. Just a thought.

Sprig, if all else fails, I'll be thinking about your suggestion!

So you live on Salt Spring eh?

A very good buddy of mine used to live there, his Mom still does, his Dad recently passed.

Another buddy, this one from Tokyo, his Japanese wife and their son live there.

Small world!

Salt Spring is one VERY nice place to live, enjoy it!

Cheers!

 

[Stu in Tokyo]

OK the muffler retrofit is done, and the carb is rebuilt, and all systems are a go!!

I decided to use the Black Hole&quot muffler, as it was a lot quieter than the RMX Muffler.

Here is the view from the bar end, the muffler is fairly secure in the muffler box, but I put a support on it just to be safe.

I also finally put a handle on the milling frame, this will make it a lot easier to use

Here is the backside view, don't laugh at my bailing wire clamp, I've got a big hose clamp here somewhere, I just cannot lay my hands on it right now.

 

[Stu in Tokyo]

The Carb Rebuild
All went well with the carb rebuild, the saw sure seems to run a lot better now. When I plucked out the smaller welsh plug, I found this ball of fuzz under the plug,........

There is a small screen in the bottom of that hole, I don't know how the fuzz got there, but it looks like wood fiber and even flecks of paint.It is all gone now, and the saw seems to be running well, tomorrow I head to the wood lot to try the new and improved set up.

Cheers!

 

[timberwolf]

That is the length from the piston face to roughly the end of the reflective cone or where the muffler goes into the outlet pipe.

 

[HiOctane]

Stu,why not add a rubber damper like you see on motocross between your pipe and the bracket.I think i will add a bracket from your exhaust studs to the case to avoid breaking your studs in the cylinder.

 

[Stu in Tokyo]

Well I'm going out in the morning to the wood lot, so I'll se how it goes.

The pipe may not look so well supported, but it is.

Cheers!

 

[amissionaryman]

Stu,
Why did you switch from the aluminum canister to the steel one?

 

[bikepilot]

The "black hole" mufler looks exactly like the one that came stock on my old KDX200. Made virtually no noise, but very heavy.