Daydreaming about tuned pipes

[Boleclimber]

Building your ow in way more fun an rewarding than buying a made pipe. Two Stroke Performance Tuning has a entire chapter on pipes and how to construct them. Using formula calculations and excel is as much fun as building the pipe. A mig welder, a sheet of sheet metal, hammers and a few hours is all you need. Practice (and a tig welder) from there if you want a pretty pipe like those pictured.

http://www.thriftbooks.com/w/two-st...n=1859606199&pcrid=70112903232&pkw=&pmt=&plc=

 

[hal9000]

Thanks for all the good replies (even the jokes) everyone. I do appreciate it.

Boleclimber, If I was retired, then building my own would be a great project, but for now, being able to modify something and get some benefit for minimal time/money investment will have to do (Hell, I only have about $40 invested in the saw anyway).

By the way, do most people leave the pipes hanging straight off the side of the saw just because it's less work than bringing them in close and they aren't using them in the woods?

 

[Blokhead]

What motor?
250's were the only 2 cylinders I remember.
The seat tells me you might want to get your chin close to the handle bars


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Polaris XC700 snowmobile engine. I used this old software;
https://web.archive.org/web/20030202224221/http://tsrsoftware.com/index_2.html

 

[jeepyfz450]

Nobody I have ever met runs a piped saw in the woods. Piped saws are for racing

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[hal9000]

Nobody I have ever met runs a piped saw in the woods. Piped saws are for racing

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Kinda figured that was the case, especially seeing the pipes people are using....

But (this is just me being petulent), if a pipe with a relatively wide, moderate effective range (not that anybody uses their saw at anything but full throttle) could be close fit to the saw, is there any reason not to use it? (I mean, except for adding a couple pounds, having a big fat wart hanging off one side of the saw that makes it hard to use in close spaces, being noisy, and the like.... ). Seriously though, I'm kind of surprised none of the mfr's have started using some kind of tuned exhaust right from the factory. Is it just an issue of dimensional restrictions?

 

[Magic_Man]

I'm in the same boat as you in that I would love to build a pipe saw just because. Not for racing, but actually use it. Maybe this winter I will find some time to start rolling some steel and welding.

 

[bikemike]

Morning all,
Right off the bat, this is more of a "what if" thread than anything. I don't have the time for another project (but I always have time to think about silly stuff like this)

So, I work at a University, and there are a handful of those DIY motorized bikes around the campus running small (50-80cc I believe) 2 stroke engines. The other day, I noticed the physical similarity between those motors and the motor in my MS390. Of course that got me wondering....

I know that there are tuned pipes available for those conversions, and the similarity got me wondering if there's any chance that the pipe from one of those bikes would be even close to appropriately sized for a similar displacement chainsaw. I had the chance to handle a broken one a while back and holding it up against my saw, it was even configured pretty well in terms of shape.

I know that pipes are designed around a specific rpm range and displacement. I don't know enough about the math to evaluate the performance potential of one of those pipes, but I figured that since every piped chainsaw I've seen looks like a custom job somebody around here might know how far off center this idea is likely to be. I wouldn't expect an off the shelf fit, but if it could be made to work with slight modifications (IE, mounts, changing the flange or headpipe, maybe a little sectioning), it might make a fun weekend project for someone's knockabout saw (Plus I'd love to see someone give it a try!)

Thanks guys.

Well I have tried the pocket rocket pipe it worked, but needed a shorter header pipe. then I did a moped pipe from vachina with cheep stainless and it worked out great with lots of shortening on the header end too. I like a pipe on a saw the looks, sound run tin tin, and the torque gains really help. the pipe on the bike kits really don't do too much as a performance booster cause they just didn't put any thought into performance vs selling a so called performance part to make a Lil more money.

 

[bikemike]

Well I used a pipes saw in the woods and milled with a poulan 46cc piped saw 20 inch bar and had no mercy on that saw and didn't overheat it either tank after tank

 

[hal9000]

Good info, thanks bikemike.

 

[B440]

 

[1Alpha1]

I could be wrong, but that don't look like no stock saw to me.

 

[Homelitexl903]

Thanks for all the good replies (even the jokes) everyone. I do appreciate it.

Boleclimber, If I was retired, then building my own would be a great project, but for now, being able to modify something and get some benefit for minimal time/money investment will have to do (Hell, I only have about $40 invested in the saw anyway).

By the way, do most people leave the pipes hanging straight off the side of the saw just because it's less work than bringing them in close and they aren't using them in the woods?

A piped racing saw is a completely different build and set up than just putting a pipe on a saw. I wouldn't mind a normal saw with a pipe in my collection for a random cookie or buck or noodle but wouldn't want that set up all day long firewood cutting and I think it would be risky for the saw and myself for felling or limbing with a brittle hot clumsy pipe. Besides a normal muffler mod these are the "dual exhausts or double barrel shotgun mufflers" work saws seem to get.

 

[hal9000]

A piped racing saw is a completely different build and set up than just putting a pipe on a saw. I wouldn't mind a normal saw with a pipe in my collection for a random cookie or buck or noodle but...

Could you expand on this a little please. I'd just like to make sure that I'm getting the right takeaway here. I'm assuming that by "piped saw" you mean the heavily modified saws like the husky that blsnelling posted.... as cool as those are (and I'm glad to have seen them), they never really were the central topic of conversation. I was thinking more along the lines of the couple homegrown/modded pipes that people have added to stock saws like bikemike's for moderate performance gains. So far, all of those are way bigger and bulkier than what I was thinking about and I'd never run a saw like that. The pipe that got me thinking about the subject is small enough (narrower cones with a longer belly) to tuck in close to the saw so that a gearhead tuner (or an idiot) like me might rationalize running it if it produced any benefit at all. Admittedly I don't have the slightest idea whether it would enhance performance, but that was kinda the point of asking the question in the first place. Since nobody else has anything even close to matching it I'm guessing it's not viable. But I might try doing some reverse engineering with one of the pipe design programs this coming weekend if I have a free moment.

I'll go snap a photo or two just to give you an idea why I was considering it.

 

[hal9000]

Slightly different beast than what people are actually using. When I asked my original question, I honestly was expecting other setups to be similarly sized.... I didn't expect to find out people were recycling KX250 pipes onto their chainsaw though.

 

[Ted Jenkins]

Very interesting thread. I started a motorcycle shop 50 years ago and made custom exhaust for at least 20 years then got hired by a corporation to tune. A two stroke is not a motor until the exhaust is fitted to the cylinder. The biggest improvement for pretty much any two stroke is the exhaust. Whenever I have any reason to tear down a saw the muffler gets opened and enlarged as much as there is room. As far as a tuned pipe for a production saw not too practical but allowing the motor to breathe a bit better will yield much improvement. A professionally tuned 80cc motor could produce 30BHP without much effort, but it would not be compact, quiet, smooth or without constant tuning to get your logs cut open. In my case I am happy to get a better breathing work horse that is manageable. Thanks

 

[bikemike]

View attachment 537552 View attachment 537553

Slightly different beast than what people are actually using. When I asked my original question, I honestly was expecting other setups to be similarly sized.... I didn't expect to find out people were recycling KX250 pipes onto their chainsaw though.

I'd run that on lot clear jobs

 

[B440]

Any one of these motorized bicycle pipes is an improvement on the the 38cc saw by a wide margin. I'll be trying one on a 45cc Stihl at some point. The chrome banana has potential; I just need to cut, turn and tuck it to the side and it'll work for nearly everything except cutting at ground level.

The 034 (56cc) was being held back and needs a bigger pipe. The exhaust port was almost twice as big as the pipe header opening.

 

[bikemike]

Any one of these motorized bicycle pipes is an improvement on the the 38cc saw by a wide margin. I'll be trying one on a 45cc Stihl at some point. The chrome banana has potential; I just need to cut, turn and tuck it to the side and it'll work for nearly everything except cutting at ground level.

The 034 (56cc) was being held back and needs a bigger pipe. The exhaust port was almost twice as big as the pipe header opening.

That's right up my alley buddy the black tuned pipe and the grey pipe you should cut the header tube down some to shorten it. the pipe on the echo was long like the pipe on ur stihl and grey saw. It runs really good for some mild port work and no compression increase

 

[bikemike]

Any one of these motorized bicycle pipes is an improvement on the the 38cc saw by a wide margin. I'll be trying one on a 45cc Stihl at some point. The chrome banana has potential; I just need to cut, turn and tuck it to the side and it'll work for nearly everything except cutting at ground level.

The 034 (56cc) was being held back and needs a bigger pipe. The exhaust port was almost twice as big as the pipe header opening.

16 inch maple passing the pipe

 

[B440]

I like the silencer in the first vid! No silencer on a pipe is ear-splitting even with earmuffs. All of the pipes I have do a good job of silencing.

I like how the last guy launches the cookie in the second vid.