Exhaust Repair info.


Information and questions on GL1200 Goldwings (1984-1987)
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Rusty Bike
Posts: 267
Joined: Sun Feb 28, 2016 1:55 pm
Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Exhaust Repair info.

Postby Rusty Bike » Sun Jul 10, 2016 8:57 am



My pipes are rusted out at the joint between headers and mufflers, were the 2 bolt clamps go. I have them on the bench.
Note: The OEM gaskets on my bike look like asbestos to me so take the proper precautions when disassembly and prep work is preformed. Wetting down area will keep dust down and wear a good quality resperator with rated cartrage.
Was able to remove the chrome muffler shrouds by heating screw bases dull red with cutting torch turned down low. Screws came right out! I found that
1 1/4" rigid conduit is very close in OD to the rusted header ends. Plus it is galvanized inside and out. I used 2" EMT conduit for the muffler mouth. Can you tell I am
an electrician! This had to be split and srunk then mig welded to get proper diameter as I could not find proper size tubeing . I used the new OEM muffler gaskets as a size guide. New parts slide together nicely with gaskets inserted. Welding the replacement parts into place is tricky due to alinement problems. Today I will reinstall exhaust system and tack the new peices in place to insure proper alinement.
Question: What precautions should be taken to protect the bikes electrical system prior to welding? I will disconnect battery but is there anything else? Thanks...Rusty



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twocams
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Motorcycle: 1985 GL1200 Aspencade, 2003 K1200GT BMW, 1969 R69S BMW
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Re: Exhaust Repair info.

Postby twocams » Sun Jul 10, 2016 10:32 am

Think you could shoot a couple pictures? I never had one of these apart and have know idea what you're talking about. You lost me at exhaust.
Unhooking the battery should do it....but. Think I would unplug the computer, and charging system stuff. But I would rather be safe than sorry. :shock:

twocams

Rusty Bike
Posts: 267
Joined: Sun Feb 28, 2016 1:55 pm
Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Re: Exhaust Repair info.

Postby Rusty Bike » Sun Jul 10, 2016 9:07 pm

Here are the pics. I should have used the Macro setting on camera.
Attachments
2" thinwall conduit welded to muffler
2" thinwall conduit welded to muffler
1 1/4" rigid conduit nipple
1 1/4" rigid conduit nipple
Trial fitup and nipple tacked into place on bike. This will work great!
Trial fitup and nipple tacked into place on bike. This will work great!

purplerider1200
Posts: 7
Joined: Sat Jul 12, 2014 10:42 pm
Location: South Bend
Motorcycle: 75 Goldwing, 84&86 interstates

Re: Exhaust Repair info.

Postby purplerider1200 » Sun Jul 10, 2016 10:28 pm

Did that before. And I used emt also. Now, obviously it is too small. But, I had a large socket that was the correct diameter. I took that socket and pressed it inside the emt using a bench press. It worked fine, but keep in mind that the galvanizing burns off during welding. Don't breathe in the smoke- that's toxic!

Check the inside header pipes for cracks or even broken internal pipes. I had three that were broke completely off. Fixing that was surprisingly easy. I cut the exterior part of the way out, welded the interior part back together, and welded the section I cut away back in place. Neat part- by cutting only part of the exterior, the interior was held in place. Since I know how to gas weld, I found it was easier to deal with than electric.

Rusty Bike
Posts: 267
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Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Re: Exhaust Repair info.

Postby Rusty Bike » Tue Jul 12, 2016 6:43 pm

Mr Purplerider, I took a look in those header pipes for cracks. No cracks. What I did find was large weld beads at the flange where the pipes hit the head. These welds were causing a necked down area at the flange that appeared to limit the flow of exhaust. I took the die grinder and a rotary file to the welds , smoothed and reduced the weld profile. This should eliminate backfire causing hot spots and increase exhaust flow due to increased ID. Thanks for getting me looking closer! ;)

purplerider1200
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Motorcycle: 75 Goldwing, 84&86 interstates

Re: Exhaust Repair info.

Postby purplerider1200 » Wed Jul 13, 2016 6:10 pm

I found that also in mine. Once yours is put back together, there are weep holes in the header pipes, near the back of the headers. Check those for exhaust gases while it's running. If it's coming out, you've got a cracked head pipe.

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alanc1100
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Location: Lakewood, Wa.
Motorcycle: 1986 GL1200A Aspencade

Re: Exhaust Repair info.

Postby alanc1100 » Thu Jul 14, 2016 1:18 am

Hi Rusty,
I have the same problem. The only parts that actually rusted through were the tabs on the front of the muffler assembly that are above the gaskets and get clamped down. Bought some decent HD slip-ons for cheap and had a muffler shop bend me two lengths of tubing. I put it together and started the bike. It ran very poorly and had to use full choke. Even after ten minutes of running, it still took about half choke to keep it running. So, after seeing your posts, I'm going to try welding new tab ends on the stock mufflers. Maybe it'll actually run right after that.

Alanc1100

Rusty Bike
Posts: 267
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Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Re: Exhaust Repair info.

Postby Rusty Bike » Thu Jul 14, 2016 7:08 pm

OK, just to try n help. For the muffler I used 2" EMT tubing (Thinwall electrical conduit) and cut suitable lengths to replace the clamp tabs. This tubeing is too big in diameter as is. You may be able to find a better fitting piece of pipe at a muffler shop or auto parts. To reduce the diameter I split the tube peices lenghtwise . I then cut slivers lenghtwise while squeezing the ring with channellocks till I had the ID the correct size to fit snugly over a new OEM muffler gasket/bushing. I then cut off the bad tabs from the muffler. The big trick here is to get the cut square so that everything lines up when installed. As you cau see in my pics, I screwed this part up. Took a lot of time to get the new nipple square with the muffler. Wrap a piece of light cardboard around the tabs and use this as a straight edge to draw a cut line on the muffler tabs. This is called a wrap around gage as used by pipe fitters. Cut on the line, tack up the new nipple, weld up the lenghtwise split then weld the nipple to the muffler. I use a MIG welder. You may want to lightly grind off the galvanized coating from the EMT before welding. Be careful of the fumes when welding galvanized anything, the fumes will make you ill. The antidote for this illness is milk! After welding do a test fit on the bike with the header pipes, if all looks well use a cutting wheel on your angle grinder to cut the slots in the new nipples. Since then, I have cleaned the headers up with a wire wheel and sprayed them with several coats of 1200 deg. Rustolum stove paint available at Home Depot. I did not use the wire wheel on the mufflers as I did not want to mess up the silver coating (galvanizing?) that is under the black paint. I just used a wire brush and elbow grease on the muffler. Good luck alanc. Hope this helps...Rusty
Last edited by Rusty Bike on Thu Jul 14, 2016 9:09 pm, edited 3 times in total.

Rusty Bike
Posts: 267
Joined: Sun Feb 28, 2016 1:55 pm
Location: New castle, PA
Motorcycle: 86 GL1200 SEi, 78 Yamaha XS750SE, 86 Honda XL125, 4.5 HP belt drive Minibike my dad built, foot clutch!

Re: Exhaust Repair info.

Postby Rusty Bike » Thu Jul 14, 2016 7:09 pm

Thanks for that tip Mr Purplerider, good stuff!

purplerider1200
Posts: 7
Joined: Sat Jul 12, 2014 10:42 pm
Location: South Bend
Motorcycle: 75 Goldwing, 84&86 interstates

Re: Exhaust Repair info.

Postby purplerider1200 » Thu Jul 14, 2016 7:51 pm

Hope it helps. Seems to be my hobby, fixing rusty GL mufflers. At least fixing them has improved my gas welding skills.

CrystalPistol
Posts: 259
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Location: Shenandoah Valley of Virginia
Motorcycle: 1985 GL1200A
1997 GL1500SE Lehman Trike

Re: Exhaust Repair info.

Postby CrystalPistol » Fri Jul 15, 2016 8:21 am

Buddy had an '85 GL1200 I that had leaking exhaust. Rotted at the junctions. He found a good muffler assembly for $100 or less on ebay so that was good ..... but then the spigots on the header sets were bad too. I got some pieces made to replicate oem sizes at a local muffler shop, expanded to exact what I needed, cut out old and welded in new .... worked great.


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