Join Date: Sep 2004
Location: Albuquerque, New Mexico, USA
A few weeks ago I was in a dilemma. I needed a new exhaust for my ’77 GL1000. New one’s are no longer available from Honda, and aftermarket is still pretty expensive. Expensive to me because I’m a full-time student and money is certainly not a thing I have in abundance.
In abundance, however, is my ability (willingness) to turn a wrench. I was an Air Force aircraft mechanic for 21 years.
There sure are a lot of very noisy Harley Davidson motorcycles on the road these days. Most of them didn’t come from the factory that way – the owners took the stock mufflers off and replaced them with aftermarket pipes to make them belch even louder. They call them “slip-ons.”
The Harley model that is probably most common, is the Sportster. Sportster stock mufflers, with a little tweaking, will fit pretty well on a GL1000 (maybe others too). Since the owners of these Sportsters no longer have a use for their OEM stock mufflers, the mufflers end up on ebay.
I got a pair from a 2001 Sportster with 350 miles on them for $26 + shipping. When buying them, make sure that the original baffles are still installed – some Harley guys punch them out for more decibels. Also make sure they have mounting tabs welded on the sides… I think some don’t.
Here’s what I did.
The stock GL1000 header pipes are not an exact fit for the Sportster mufflers. I took stainless steel sheet metal .010” thick and made shims to fit between the mating surface of the muffler and the mating surface of the header. I used three .010” shims per side. If I were to do it again I would use one shim of .028”. Make sure the entire mating surface is covered (for a good air seal and clamping strength). The sheet metal can be found at art supply and hardware stores.
For clamps I used standard Harley parts. I got a pair for $5 from a Harley mechanic who had them sitting in his toolbox from all those “slip-ons” he installed. New they are $8.50 apiece.
To support the weight of the muffler, I used some galvanized steel ¾ inch wide and about 3/16 inch thick and cut and drilled to size.
Re-jetting… maybe. I re-jetted a little richer to compensate, but mostly to eliminate the off-idle glitch common with the early wings.
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\'77 GL1000 (sold)
\'08 Suzuki V-Strom DL650
\'99 Ducati 900ss
\'97 Honda XR650L