Stainless exhausts

[090]

Can they be used/made? Or are there reasons why i dont ever see one, especially headers made from it.

[E74]

on a two stroke?, too expensive! and It holds heat.

[Maico31]

Brad we've used stainless mufflers on our 4 stroke Husky's at work when the titanium ones have been totalled. I'm pretty sure the enduro models have stainless headers standard.

[mx250]

on a two stroke?, too expensive! and It holds heat.

To hold heat in the exhaust is to hold energy in the exhaust gases. In theory that is a good thing for power.

[oldfart]

Brad there is no real reason except for cost factor ....having built 2 systems out of mild steel in the last month .  Another point it walks all over the place when you do ya final weld , some say the joints crack after some time ( requires gas inside and sealed at one end of the pipe ) for the perfect weld
                 
                 

[Lozza]

There a plenty of 2T chambers made from Stainless but they are maily for road bikes(TYGA, Lomas etc), the facts it's prick to work with and the cost, it changes the characteristics of the waves within the pipe that makes stainless unsuitable for off road use.As mx250 mentioned retaining heat is a good thing but there are million variables.Best material is Ti followed by humble mild steel.

[firko]

I once build a Maico expansion chamber out of 18g 314 stainless steel. It sure looked pretty once polished but was destined to fail for a number of reasons.
1: It's about 20% heavier than mild steel.
2: It work hardens with heat and becomes quite brittle.
3:Unless you are of the habit of taking a TIG welder to the races with you, you are up shit creek if a crack develops during a race meeting (and you can bet your goolies it eventually will crack)
4: It does indeed hold heat thereby decreasing HP to a minor degree and possibly affecting jetting as heat increases (I'm not certain on that, just a suspicion)
5:It's almost impossible to neatly panelbeat dings out of staino. It can be done but it's ugly.
6:Stainless steel is expensive. I built my pipe as a foreign order at work using old hospital linen trolleys and operating tables as donor material.

One advantage of stainless steel is that it's extremely easy to weld if you know what you're doing. There's no need to purge the material like Oldfart suggests. That's a neccesity for titanium. Unfortunately you are stuck with TIG or MIG which counts out home or trackside repairs as I earlier stated.
I've still got my staino pipe which I keep as a shrine to "it was a good idea at the time"

[090]

Thanks for the replies. Dad asked me to consult the forum as he thought it would be a good idea as a bling factor.
I will tell him to put it in the too hard basket( his own as mine is already overflowing).
Cheers, Brad

[GMC]

I have been asked a few times over the years about building stainless chambers, but I have also put it in the too hard basket.
Mostly because I believe they would crack due to work hardening like Firko stated, also its a stiffer material to start with which is what makes it harder to form into a chamber. I do build 4 stroke pipes from stainless which seem to last okay & it is preferable to purge (gas inside and sealed at one both ends of the pipe) the weld to achieve the best penetration to safely remove the outside weld to polish smooth.
Ti is a good material but I have had to weld a few Ti pipes that have cracked from fatigue, some of these nare not very old at all & some muffler bodies I have replaced with alloy for bugger all weight gain.
Their were some alloy chambers on Trials bikes in the mid nineties, Beta's I think. They seemed to last okay, but a trials bike doesn't get a work out like a MX bike does. Not sure if their are any alloy chambers still being built.

Mild steel sounds boring in this high tech world but it is very durable material for chambers