OEM Exhaust Question

[derek533]

Hey guys, my left side OEM exhaust has an exhaust leak somewhere inside the resonator.  I had been dealing with it by JB Welding the entrance of the piggies into the resonator.  However, as the JB weld cured, it shrunk a tiny amount and is allowing the piggies to rub against the JB weld creating a very annoying squeaking when going over any sort of bump or road imperfection.  I know there is an exhaust leak inside the resonator because the left side was audibly louder than the right side prior to me fixing it and you could feel the exhaust coming out where the piggies entered it.    

My question is, could a muffler shop cut open the resonator, weld whatever broke lose inside the resonator and re-weld it back?  I really don't want to spend the money people want for a secondhand exhaust, and will just keep replacing the JB weld on occasion if I have to.  If I could find a reasonable left only exhaust without the chrome shields as mine are still good, I'd got that route but people want a mint for anything exhaust related.  

Thanks.  

[psckam]

anything is possible with the right amount of $$$

[Bagger John - #3785]

Most muffler shops are set up to do MIG only.

You want this repair to be TIG welded. I'd call around a few local weld shops and see what they have to say.

MarkT might also be able to help you.

[MarkT]

If it's leaking inside the muffler and the piggies are loose, you have a corrosion problem such that the baffles inside have decayed to where there's not much left to salvage.  Especially if your pipes came from a place like Florida and have some miles on them.  Rust is a real problem there.

BTW I MIG and TIG (and gas, and stick, and braze, and solder) but the appropriate tech for thin steel is MIG. That's also what Honda does on the exhaust, and other thin-steel welds.

Also, the muffler cans are SS.  It's the baffles inside that rot. And the back end cap.  So your pipes can be used for the following.

I'm afraid your problem will require spending some $$.  And I'd say it's not going to be worth surgery on your exisitng exhaust - it's surely rotted out inside.  What I do here, is completely remove the inside baffles, retain the can walls to act as the exhaust system frame, and replace the baffles with a header collector and glasspack.  Which is MUCH thicker steel than the OEM baffles and will outlast the bike. And make more power, and have a great sound that's not too loud to be obnoxious.  And made for a V8 engine; this little 1.5 liter engine can't get it hot enough to burn it out and need replacement.  The basic glasspack mod using your OEM covers is still offered at $499, same price (almost) as I did it 24 years ago ($495).  It's the stacks and other steel that has gone crazy in cost (thanks Uncle Joe) - and shipping is up, too.  The glasspacks cost me more, but I'm absorbing the cost in my reduced margin.  There are other mods I offer as well, but sounds like you are on a budget.  See http://www.horseapple.com/Valkyrie/Valk_Products/M2W_Exhaust__System/m2w_exhaust__system.html

[RonW]

I think the only way is to weld it from the outside. Like how you did the JB Weld.





There's too many things in the way inside the cannister. To begin with, you'd have to open up the cannister and once there, there's the separators to deal with (red in graphic below).
That 'bulge' in the pipes might obstruct any interior welding too. The factory might have only wielded it from the outside anyway. I guess the chrome muffler tip wasn't there only for decoration.

[Bagger John - #3785]

BTW I MIG and TIG (and gas, and stick, and braze, and solder) but the appropriate tech for thin steel is MIG. That's also what Honda does on the exhaust, and other thin-steel welds.

Bolded first:

TIG process allows much finer control of the welder waveform (including current) than MIG, especially when you get into the Syncrowave or TIG-3xx class of equipment.

I can consistently put a bead down the edge of a razor blade without burn-through using a higher-end TIG welder. Try as I might, I've never been able to repeat that with any MIG setup I've played with.

Italicized next:

MIG readily lends itself to process automation, whereas TIG does not. The latter requires a skilled human operator.

Honda got bit REALLY hard vis TIG to MIG on the 2003-2004 year GL1800. Some bean counter"process improvement engineer" switched the weldment operation for the frame's lower shock mount from TIG to MIG. I haven't read the final NHTSA metallurgy report on the associated recall (due to frame breakage) but it's a safe bet to assume inadequate penetration and improper waveform taper-down led to areas prone to stress cracking.

Should the process engineers have bothered to study various welding industry rags concerning post-incident analysis, they'd have found this very same problem bit Boeing in the a$$ in the 70s.

[98valk]

BTW I MIG and TIG (and gas, and stick, and braze, and solder) but the appropriate tech for thin steel is MIG. That's also what Honda does on the exhaust, and other thin-steel welds.

Bolded first:

TIG process allows much finer control of the welder waveform (including current) than MIG, especially when you get into the Syncrowave or TIG-3xx class of equipment.

I can consistently put a bead down the edge of a razor blade without burn-through using a higher-end TIG welder. Try as I might, I've never been able to repeat that with any MIG setup I've played with.

Italicized next:

MIG readily lends itself to process automation, whereas TIG does not. The latter requires a skilled human operator.

Honda got bit REALLY hard vis TIG to MIG on the 2003-2004 year GL1800. Some bean counter"process improvement engineer" switched the weldment operation for the frame's lower shock mount from TIG to MIG. I haven't read the final NHTSA metallurgy report on the associated recall (due to frame breakage) but it's a safe bet to assume inadequate penetration and improper waveform taper-down led to areas prone to stress cracking.

Should the process engineers have bothered to study various welding industry rags concerning post-incident analysis, they'd have found this very same problem bit Boeing in the a$$ in the 70s.

great info.   

I would surmise the honda incident is related to wanting to use a robot to weld and not a human.

[derek533]

I think the only way is to weld it from the outside. Like how you did the JB Weld.

For clarification, my problem isn't where the piggies exit the canister but rather where they enter the front baffle at the front of the canister.   Before I repaired it with the JB putty, you could physically feel the exhaust pulses coming from the front baffle plate going towards the front of the bike.  All I'm doing by putting that putty around the entrance is hoping to keep the exhaust going rearward as God intended. 

[derek533]

If it's leaking inside the muffler and the piggies are loose, you have a corrosion problem such that the baffles inside have decayed to where there's not much left to salvage.  Especially if your pipes came from a place like Florida and have some miles on them.  Rust is a real problem there.

Funny thing is, this is a 100% pure Oklahoma bike and not Florida or some humid climate.  Yes, we get humid in the summer, but it's only seasonal and are winters are dry enough to crack your hands and fingers by just looking at them. 

Thanks for your insight.  I may very well end up giving you a call if I can't find a solution or just get lucky and find someone selling a left side for a reasonable amount that hasn't been beat to crap. 

[RonW]

This kind of repair is better done by a metal fabricator. Most metal fabricators can't repair engines and not all muffler workers wield good or have the necessary tools.

[edit]

Btw, the separators are spot wielded to the cannister from the outside. To peel off the cannister, you'd have to drill out the spot wields.

[derek533]

This kind of repair is better done by a metal fabricator. Most metal fabricators can't repair engines and most mechanics don't wield good or have the necessary tools.

[edit]

Btw, the separators are spot wielded to the cannister from the outside. To peel off the cannister, you'd have to drill out the spot wields.

I guess the real question becomes since I now see how these are made and thanks for posting the diagrams and pics, what would cause the exhaust to come back out the front baffle plate and not continue towards the rear.  In other words, I'm trying to wrap my brain around what would go wrong inside the canister to not allow the exhaust to continue to flow rearward and also audibly, be louder on one side?  

[RonW]

For clarification, my problem isn't where the piggies exit the canister ..... but rather where they enter the front baffle at the front of the canister.

I missed your clarification. I incorrectly thought the leak was from the rear part of the cannister.

Anyways, pics of cannister's front section from QueXpress' writeup. I would trying wielding a bead from the outside to seal off the leak.
However, I don't know how difficult it is to avoid burning through the metal plate. Probably safer with Tig or mig than stick wielding.

[Bagger John - #3785]

...great info.   

I would surmise the honda incident is related to wanting to use a robot to weld and not a human.

You would be correct.

MIG has its places. That frame weldment wasn't one of them, but when your bean counters (instead of your metallurgists) run the production lines...

[MarkT]

...great info.  

I would surmise the honda incident is related to wanting to use a robot to weld and not a human.

You would be correct.

MIG has its places. That frame weldment wasn't one of them, but when your bean counters (instead of your metallurgists) run the production lines...

I would add, correct.  Yes TIG welds can be gorgeous, when done by a skilled welder.  But not really practical for build cost reasons.  If you examine a disassembled Valkyrie exhaust, you will see the remains - stubs - of MIG weld wire.  I've not heard of a robot TIG welder (but maybe they exist, haven't researched that).  Manual or robot, here they are MIG.  Honda's MIG exhaust welds are suspiciously uniform, so I'd bet they are robo-welds.  As for me, I use MIG FAR more than TIG.  They are quick, inexpensive, strong, and good enough looking for most everything I need to weld.  Though my frame weld on my 2002 GW 1800 recall, was aluminum TIG.  BTW, both MIG and TIG tech is available for steel and aluminum.

I have not tried to weld literally a razor blade.  But I have MIG welded very thin steel.  Down to known, 22ga.  You need to be spot-on on the volt setting & time of the arc.  Of course, wire speed matters too.  You need a quality welder with infinite power setting - not click stop volt settings (like the cheap, dumbed-down welders Lincoln makes for the big-box stores).  My preferred is a Lincoln Dual Power 180 welder.  Though I have burned out 2 more, and have a Lincoln 180 HD model (got a deal, found out it's a dumbed-down one I mentioned)  Also have a spool gun to feed aluminum MIG, for the Dual Power.  For non-welders, you can't feed aluminum wire through the usual feed, from the spool at the power box.  It will jam feeding that far.  The spool gun mounts at the torch end of the gas/power cable.  
I use a Lincoln TIG 200 Square Wave for my occasional TIG welding.  It's a small-shop machine, not a multi-thousand $ high-production platform.  Suitable for my needs.

Secondly, Derek says he's getting leaks out the front of the can at the headers.  I have repaired this many times, always in conjunction with a custom exhaust build - easy, when building the custom pipes I have to take it apart here anyway.  Typically, the headers are loose. I put the exhaust on my jig which holds them in the OEM alignment.  Do several tack welds to hold the headers in the correct position.  Cut the can off where I usually do, about 3/8" aft of the weep hole - after making scribe marks in 4 places around the perimeter for alignment on reassembly.  Then thoroughly weld the end of the headers inside the cans, where Honda also welded it originally.  Looks like this:




BTW here's the same view inside another header collector, not broken, Honda OEM welds.  Look how small they are, and uniform.  Robo MIG welds, I'd say.  No wonder they can break with corrosion.

[Bagger John - #3785]

You need a quality welder with infinite power setting - not click stop volt settings (like the cheap, dumbed-down welders Lincoln makes for the big-box stores).  My preferred is a Lincoln Dual Power 180 welder.

I have to wire my new barn (fab shop) for them, but the two that are going in it are an STT-455 (dual-feed MIG) and a TIG-350.

The area farm boys figured out I know how to run machine tools and melt metal together, and while I probably won't get rich doing it I can see my little shop paying for itself at some point.

As an aside, the former IT Compliance Director of a place I used to work now has that spot at Lincoln. Every now and again I'll get a ping from her asking if I want to get involved in their IT Security team.

Tempting, but I don't miss the drama.