Author Topic: best way to fix this exhaust "rot"? (Read 2693 times)

amamet · « **on:** March 24, 2020, 02:04:34 PM »

well, while I was checking out my lafranconis that are going on the lemans, I noticed these 2 rot spots in kinda the indentical area. what's the best way to remedy this? they both on the top inside of the muffler

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Chuck in Indiana · « **Reply #1 on:** March 24, 2020, 02:12:02 PM »

Uhh order new? That looks terminal to me..

amamet · « **Reply #2 on:** March 24, 2020, 02:28:45 PM »

My plan was to get a new set but with what’s going on right now, nothing is available for a while. Zard was my first choice. Since these are oversized anyway 40mm where my headers are 38mm, if I make up a long inner sleeve as a shim for a tight fit, it can also extend beyond holes. I dunno, just trying to see if I can make them work

moto-uno · « **Reply #3 on:** March 24, 2020, 02:45:13 PM »

Find someone who Tig welds and maybe is a metal artist too . I like welding thin metals with the tig .
Really good torch welders could probably handle this , they're kinda pricey to replace .
Also I might recommend when remounting them to pull them up a bit at the rear mount to unload the front clamping . Peter

lucian · « **Reply #4 on:** March 24, 2020, 03:37:00 PM »

https://www.acehardware.com/departments/automotive-rv-and-marine/auto-tools-and-maintenance/automotive-adhesives/8554461?x429=true&gclid=CjwKCAjw3-bzBRBhEiwAgnnLCrVWF5UEKOVMIlIJMEYDZ5cRvLquLtW4ZqZWxE_2h_T9T4kHazqBqBoCo20QAvD_BwE&gclsrc=aw.ds

Perazzimx14 · « **Reply #5 on:** March 24, 2020, 03:37:52 PM »

Quote from: moto-uno on March 24, 2020, 02:45:13 PM

Find someone who Tig welds and maybe is a metal artist too . I like welding thin metals with the tig .
Really good torch welders could probably handle this , they're kinda pricey to replace .
Also I might recommend when remounting them to pull them up a bit at the rear mount to unload the front clamping . Peter

But you have to have good metal to weld too. I'm sure as soon as the TIG torch arc's a big hole will appear where the rusty worn metal just falls away.

wicks · « **Reply #6 on:** March 24, 2020, 04:00:44 PM »

Could always try the old JB weld.

moto-uno · « **Reply #7 on:** March 24, 2020, 04:34:57 PM »

Usually they'd make a small number of patches extending into the sound metal . It's only steel , so nothing fancy to fabricate . Peter

wirespokes · « **Reply #8 on:** March 24, 2020, 04:54:06 PM »

I like the idea of shimming, but you're talking about a piece of tubing .040" (1mm) thick. Oughta be interesting rounding up something like that. You could maybe turn down something like that on the lathe.

The way I see it going is welding up the crack, then grinding the inside smooth with a dremel or die grinder. There is chrome rod you can use in the arc welder, though I'd prefer going with gas. Don't know if you can use chrome rod gas welding.

I've gas welded holes in automotive mufflers and they're lots thinner than what you've got. Weld it up, smooth it out a little (if needed) then paint the weld with some chrome or silver paint. Probably wouldn't look bad and could work for several more years.

Stevex · « **Reply #9 on:** March 25, 2020, 06:21:03 AM »

Trouble with the Lafranconi Competizione is they rot from the inside.

Chuck in Indiana · « **Reply #10 on:** March 25, 2020, 06:49:48 AM »

Quote from: Stevex on March 25, 2020, 06:21:03 AM

Trouble with the Lafranconi Competizione is they rot from the inside.

That's why I said

Quote

That looks terminal to me..

As soon as you touch it with a torch it'll disappear. A pin hole turns into big hole. BTDT.

JJ · « **Reply #11 on:** March 25, 2020, 09:00:22 AM »

QUOTE: "Best way to fix this exhaust rot"?

From that photo, I would say a new, (or gently used), set of exhaust pipes are in high order...

amamet · « **Reply #12 on:** March 25, 2020, 09:28:10 AM »

again, yes, I planned on getting a new set of pipes, but I don't think Zard (they are in Italy) is going to be producing and shipping anything anytime soon

britman · « **Reply #13 on:** March 25, 2020, 11:44:28 AM »

On old ones that you just have to save and ideally the rust patch is not all that visible, I have used a malleable piece of metal, (an old motorcycle license plate is perfect if you work it awhile with a hammer to really make it fall into the needed shape) rivets and JB Weld. Lay a good base of the JB around the hole and on the back of the metal patch, rivet the piece in to good surrounding metal, let it set, cover with chrome or aluminium paint, and go on with life. They will gig you if you go to the Pebble Beach Show, but for a everyday rider, the fix works well......

britman · « **Reply #14 on:** March 25, 2020, 11:51:02 AM »

Forgot I had some shots where I did this to an set of unobtainable Honda CB500 Four pipes, damn sure not pretty but it seals..

image uploader

Furbo · « **Reply #15 on:** March 25, 2020, 03:49:08 PM »

I have a complete LeMans V exhaust I'd love to sell. Good shape, Chrome.

Monza-jockey · « **Reply #16 on:** March 25, 2020, 07:59:58 PM »

Check what these folks might have:

http://www.keihan.co.uk/

Bought a nice stainless exhaust (headers, H pipe crossover and mufflers) for the Monza.

Everything went on on in 30 minutes.

Cam3512 · « **Reply #17 on:** March 25, 2020, 08:10:44 PM »

All those repairs look like crap. Find another set.

britman · « **Reply #18 on:** March 25, 2020, 10:09:08 PM »

Quote from: Cam3512 on March 25, 2020, 08:10:44 PM

All those repairs look like crap. Find another set.

I said from the get go, it was not pretty, but would work as a temporary fix or on a set that there was no replacement for as the OP stated. Just throwing up a fix that has worked for me in the past, not everything in life is a beauty including myself and my cat.......

Perazzimx14 · « **Reply #19 on:** March 26, 2020, 06:30:02 AM »

Save the chewing gum and aluminum foil repairs for an emergency. Worst case is if you need mufflers now find a temporary set. There are ton of Harley mufflers out there than can be adapted fairly easily and cheap. Then when Zard is back up and running order what you want.

amamet · « **Reply #20 on:** March 26, 2020, 07:44:27 AM »

I have some .032" aluminum sheets that im going to try to fashion into a reducing "tube" and set the length to go beyond the damage. hopefully it'll seal well enough that the back flow won't migrate back. ill find out when she starts anyway. In the meantime im putting in an order at Zard after chatting with them, ill get them when I get them, they are offering 15% till the end of the month. that discount was around even before the virus crap. its expensive but it the best looking lemans exhaust ive seen, aside from the guzzi performance open racing exhaust that is

Perazzimx14 · « **Reply #21 on:** March 26, 2020, 08:45:59 AM »

Aluminum foils also works. Take a sheet about 8" long then foil it over and over into a 1-1/2" strip. The wrap around the male end and push a little over the end of the exhaust to hold it in place until you can slip the female end over. It may take several layers.

RinkRat II · « **Reply #22 on:** March 26, 2020, 12:28:12 PM »

With that Hi temp JB Weld you could take Header Wrap to a whole new level

Paul B

Two Checks · « **Reply #23 on:** March 27, 2020, 10:16:28 AM »

I used Mountain Dew cans and hose clamps (Guzzi content) on a 75 Wing many moons ago.

booob · « **Reply #24 on:** March 27, 2020, 11:02:59 AM »

Easy fix, cut out a square hole around the rusted area, cut a square from a new piece of steel (no license plates) and tig in place. I've fixed many old original exausts this way. Trick is not to turn the amps down too much or you don't give the machine a chance to tack quickly. Keep tacking in different spots to keep the metal from over heating until sealed, takes time but totally doable. Shaping the patch can be done just by pressing it over the exhaust by hand.

Quote from: amamet on March 24, 2020, 02:04:34 PM

well, while I was checking out my lafranconis that are going on the lemans, I noticed these 2 rot spots in kinda the indentical area. what's the best way to remedy this? they both on the top inside of the muffler

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Author Topic: best way to fix this exhaust "rot"? (Read 2693 times)

britman

britman

britman

booob