How-To Mount Harley Mufflers - GL1100

[bikerdad5]

I had road kings on yamaha venture-v4 engine, all you do is punch out all the junk and soft plugs from both muffs. used a old tire iron ground to a chisel end, then used a 3/8 dirive 21mm snapon impact socket and long extension to bend over the remaining plugs inside the muffs. Then I put 1 1.5 inch od auto engine soft plug from the engine side so it would not blow out during use, you may have to spread it out to get snug in muff but is easy to do.

[skeddie]

those sporty mufflers are cool, and look good. my 2 questions are, how do they sound? and what about the cross over tube? is that still used or is it eliminated?

[Roady]

No crossover required. Those are 2003's and did not come with one.

There are a couple of videos in the first post of this thread that'll give you a taste of the sound.

[tlbranth]

A lot of pictures are not showing up on this thread. Have any of you who've done this swap made allowance for expansion? I assume that's what the wrap-around gasket was for originally.

[robin1731]

A lot of pictures are not showing up on this thread. Have any of you who've done this swap made allowance for expansion? I assume that's what the wrap-around gasket was for originally.

I think the gasket was more for sealing and ease of removal down the road. All the aftermarket pipes I've put on use no gasket. Just a tight fit pipe to pipe. Along with a clamp. No leaks or pipes falling off.

[Roady]

I'll restore the images.

[tlbranth]

I'm looking to mount Bonneville mufflers to the '75. The muffler has a 35 degree downturn where it meets the header. So I cut up a 90 degree mandrel bend to get 2 35's out of it and welded some straight pipe to the stub ends. I figured that after fit-up when everything is cut to length, I'd weld my new pieces directly to the manifolds (after cutting off the stubs coming out of them). My new pieces would then be clamped tight to the mufflers and the mufflers hard-bolted to the rear footpeg mounts. Good idea except for expansion. Isn't something going to break in a rigid setup like that?

[robin1731]

I'm looking to mount Bonneville mufflers to the '75. The muffler has a 35 degree downturn where it meets the header. So I cut up a 90 degree mandrel bend to get 2 35's out of it and welded some straight pipe to the stub ends. I figured that after fit-up when everything is cut to length, I'd weld my new pieces directly to the manifolds (after cutting off the stubs coming out of them). My new pieces would then be clamped tight to the mufflers and the mufflers hard-bolted to the rear footpeg mounts. Good idea except for expansion. Isn't something going to break in a rigid setup like that?

There are a lot of HD pipes mounted similar to this. Just without the welding. I've heard of no one having one break. I have not had any problems with any that I've done.

[CYBORG]

I have Harley mufflers on my 77. Have for years. No problem. But they are not welded to the headers

[robin1731]

To be honest I don't like welding them up. It makes for a pretty heavy and awkward piece if you ever take them off. And much harder to change mufflers if you decide to later on.

[CYBORG]

I've never ever even considered welding the mufflers on. For all the above reasons, and a few more

[Roady]

Pics in the first post have been restored.

I also added an update covering the extensions I added to shoot the exhaust past my panniers.

[Roady]

Pictures restored in post #1.

[Winger1957]

Further update.

Still haven't been able to ride but have found that the Road Kings have too much scavenging action for my bike...

I put the Sporsters back on. ( I'd welded a 4 or 5 inch extension onto them to get the exit diameter down closer to stock & it balanced the exhaust system better. With out the extension you got the Harley potato, potato, potato sound and their was a difference in flow between the left & right side.) Immediately the bike settled down & both exhausts where fairly equal. This set up is much quieter. Throttle response was better & bike jumped to 4000 immediately with no stumble. On quick deccleration the bike didn't stumble as bad.

The Road Kings have a much bigger exhaust chamber & the exit size is about 1 5/8" and they are longer. The stock muffler's exit size is more like 1 1/4".

I just bought a used '78 GL1k that the owner abused terribly. Looking for mufflers is frustrating and disappointing, as the first GL's were the best motorcycles ever made So are these Sportster mufflers still the best choice if OEM's are unavailable? I liked your choices on the setup and performance criteria, and think yours is the best 2nd choice if I cannot source an excellent used OEM exhaust system. Please let me know if you have changed your mind toward a better solution, otherwise it seems a Sportster exhaust with a bypass tube (diameter and connection points?) and four inch extensions on the ends (does diameter matter?) and I'm good to go. The mufflers on the bike I bought are junk and will be sent to the recycler this winter.

[desertrefugee]

Welcome! I think you might find that a lot of folks that contributed to this thread have gone radio silent. The last post was three years ago.

Choice of exhaust is a pretty subjective thing, but many, many folks here have been very pleased with Harley takeoffs… Particularly the sportsters. I’m not sure why one of your criteria would be the bypass, typically if folks acquire a set with the bypass provision, they have to plug it. I was lucky enough to find a set that pre-dated that modification. It is not needed.

Also, I know that a lot of guys do use the extensions, but I installed the sportster mufflers directly onto my ‘78 header tubes. I used high temperature… Kevlar I think… Tape to fill in the gap and they fit just fine with no leaks. Clamped them down with, what else, Harley clamps.

The biggest task I had was fashioning the brackets out of steel bar stock. It’s a slam dunk.