Welding a stainless bike exhaust.

[oddball racing]

I have a fuel injected bike with a cat as part of the exhaust. There are better fuel maps that can be installed in this bike if it had aftermarket "cans" installed. Frankly, the aftermarket cans look like your carrying around acouple of Hoovers. I have already cut open the stock exhaust and carefully removed the cat section.
1)Is this stainless weldable with a standard mig?
2) ..if so is SS wire needed? Bastardization won't show as it will be hidden on the backside of the component.

I only ask because TIG is not an option I have to myself.

[macona]

BMW? My R1100R is the same way.

Probably weldable. Check if the stainless is magnetic first. Might be able to get away with .023 308 stainless wire. Stainless wire is needed. Also a gas mix for stainless. 97/3 AR/CO2 is good.

Tig would be the process of choice though.

But it may be cheaper to have someone weld it back together for you.

[gnm109]

What Macona says is quite right. Also, you really should purge the inside of the muffler with argon when the welding is being done to prevent "sugaring" of the weld HAZ inside.

[M_C]

Hijakcing this thread slightly, but if you were not to purge the exhaust, would there be any detrimental effects on the welds?

I know the stainless will get majorly discoloured (and oxidise), but would it have a big enough effect to affect strength/longitivity of the exhaust?

[torker]

Yup..there would be "detrimental" effects. You would get the sugaring mentioned. This can lead to voids or cracking. ESPECIALLY in a high vibration situation like this exhaust. If you can get in to clean it you could use Soar Flux if the weld is only one pass. Solar flux is highly corrosive and can actually weaken a weld joint if it is not removed with warm soapy water and a stiff brush.
You cannot believe the difference if a SS weld is back purged or just "left to the wind" . The backside of an unprotected weld is ugly.
Russ

[M_C]

Thanks for that.
I've got a new exhaust to make for a tractor soon, and stainless is being considered as an option. I just wasn't sure how necessary purging the back side of the weld was.

[mark61]

Hope you removed the O2 sensor before cutting or welding on that exhaust! Them things are tender.

DNAHIK!

mark61

[oddball racing]

Hope you removed the O2 sensor before cutting or welding on that exhaust! Them things are tender.

DNAHIK!

mark61

Good point for someone not in the know; might save somebody a mucho $$ headache. But I'm all set there though. KTM puts their O2 sensors in the head pipes on the SuperDuke though. Still it's good to point that out.