cracked rear exhaust pipe at Y

[oldscoolz]

i have a crack at the Y of the rear exhaust pipe on my 02 rk. ive checked out a few threads on this and havent really seen anyone who sounds like they've welded it. seems like most of the opinions fall in the category of just buy a new one. there have been some comments about metal fatigue and weld failure. i'm lookin for some comments from welders who have worked on exhaust pipe. my thinkin goes along these lines: if u can put a good weld on a relatively soft but thin steel, u should be able to put a good fix on a stress fracture in the exhaust pipe. the steel looks fine. i think i can prep it to take a good weld. i'm thinkin that an oxy/acetylene torch weld with a reasonable filler metal should fix somethin like that crack just fine. i know the devil is always in the details, and the detail here is that the metal is so damn thin. but with the right torch tip, can't this be done with a reasonable result?
ok, lets hear from some of u torch poppers and sparkers out there, who have done this stuff. thanks.

 

[Jack Klarich]

i have a crack at the Y of the rear exhaust pipe on my 02 rk. ive checked out a few threads on this and havent really seen anyone who sounds like they've welded it. seems like most of the opinions fall in the category of just buy a new one. there have been some comments about metal fatigue and weld failure. i'm lookin for some comments from welders who have worked on exhaust pipe. my thinkin goes along these lines: if u can put a good weld on a relatively soft but thin steel, u should be able to put a good fix on a stress fracture in the exhaust pipe. the steel looks fine. i think i can prep it to take a good weld. i'm thinkin that an oxy/acetylene torch weld with a reasonable filler metal should fix somethin like that crack just fine. i know the devil is always in the details, and the detail here is that the metal is so damn thin. but with the right torch tip, can't this be done with a reasonable result?
ok, lets hear from some of u torch poppers and sparkers out there, who have done this stuff. thanks.

Sure that can be done, look for all the mounts to be good, they have a nasty habit of cracking causing the pipe to break, check the motor mounts also. I would assume you will be welding the pipe off the bike ?

 

[Rydit]

Check the mounts like Jack mentioned, the rear often cracks as well. The pipe can be brazed as you mentioned, but it has to be very clean and watch the heat as it will take you south in a hurry. If you can find someone to tig weld it, the process and the results may be better, at least enough to get you by a year or two. stessed metals can have a mind of their own.

 

[CoreyV]

A TIG welder would work much better than an oxy torch. But not everyone has access to one. The heat can be more precisely placed and controlled therefore less heat put into the part. Good luck. I'd do it for you if I could.

 

[onepointman]

A friend of mine had the same problem... twice... ( He says the dealer told him that a new one would be backordered because it doesn't appear to be an unusual problem. He went to fulsac dot com and ordered the true dual conversion set from them. He likes it a lot and said it was very easy to install. took him less than an hour and he was back on the road.

 

[oldscoolz]

thanks. appreciate all the good tips. yes, i'll be takin the pipe off the bike and bench weldin. i only have two options as far as the welder. stick welder and torch (don't have a mig or tig). i have used the stick welder successfully on a sizeable crack in the neck of my handlebars, but used a sleeve in that application to help avoid burnthrough and get a good strong weld (the bars are 16" apes and have to take a little torque now and then).
for the exhaust pipes, i'm thinkin that brazin would be nice and easy but not durable. my objective is to get a good true weld on this thing. the crack is not a big gaping crack (yet) and is maybe a third of the circumference of the pipe.
would love to hear from someone who does exhaust pipe work, not puttin new pipe on, but workin with used pipe. someone in another thread mentioned usin S6 filler rod. i'm not not familiar with it. thanks again for all the good info.

 

[horizonchaser]

I wouldn't be concerned about the thinness of the steel. You can build up some nice layers of nickel spray powder alternating between cooling ( with an air hose when it gets cherry red) and applying more powder until you seal the gap. That pipe will take a nice weld. I would use a Mark 4 Oxy/Acetylene torch with a # 34 tip ( more powder applied so it builds quickly ). This torch will have a small hopper on the top of it that we fill with Colmonoy Spray powder #226.
This powder is a nickel based powder so it isn't going to rust. It will even shine fairly attractively but, and this is the main reason why I didn't do it, it will be fairly brittle. That is what caused the pipe to crack in the first place I believe so why set myself up to fail?
In a way I hope that you do weld it and report back to us that you've had no problems with it and saved yourself a lot of $$$!
Good luck in whichever you decide!

 

[oldscoolz]

thanks horizonchaser. i havent used the nickel spray powder. is this more like a bronzing technique or is it essentially a type of filler metal? are u still getting a bead- a complete melt of metal on each side of the crack and having them flow together for a true weld? has the nickel spray powder worked for u on a repair like this?

 

[glimmerman]

i am a qualified welder/boilermaker for 41 years. here is the basis of the problem. the metal is contaminated with oil residue from exhaust fumes. tig welding generates a tremendous concentrated heat. the heat affected zone around the weld then decrystalizes because of impurities and the fact that the metal has seen numerous hot/cold cycles. oxy-acetylene is a far better choice because it spreads the heat to a much larger area and eliminates the surrounding stress points in the heat affected zone. these repairs are at best marginal. it may last 2-3 years or 2-3 days. it is simply the nature of steel, heat, contaminants, and age. jmo after 41 years.

 

[glimmerman]

S-6 contains a 6% silicone load to float out impurities. use an oxweld 65 and avoid hi-tensile stuff like ER70-S6. it is much stronger than the surrounding stteel and will most surely break. DO NOT BRAZE! this is soft bronze and does nothing. the crack will propogate (get longer) and then nothing can be done.