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Hula and the Art of Motorcycle Maintenance Singing Steel - Modifying Jardine Aftermarket Pipes for a Kawasaki Vulcan 500 |
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| Background
Steve has a Kawasaki Vulcan 500. Lots of fun to ride - light, whippy, responsive, with cruiser looks. But, after 30-some-thousand miles, the crossover on the original exhaust system developed cracks. The bike was taken to a local shop. A replacement OEM exhaust system would cost around $600 before installation. The mechanic recommended using a Jardine system which, parts and labor, would run around $400. This was done. And BOY did we REGRET IT!!! The Problem The mechanic neglected to re-jet, resulting in a hot-running engine which blued the pipes almost immediately, and cooked our legs as well. The tone was horrendously loud - to the point where the guys at the local Harley hangout complained! Not only were they LOUD and OBNOXIOUS, but they were high-pitched, with a strange tinny sound, almost as if it were under water. The best description yet is that the bike sounded like a 1.5hp outboard motor being run full throttle under a concrete bridge. Complaints to the shop did not solve anything, but did result in our purchasing a re-jetting kit which is still sitting in my workshop. As it turned out, the re-jetting kit would have been excellent had we wanted to turn the bike into a wanna-be drag bike. We didn't. We like our bikes to be rather mellow, and use them more for running errands and getting groceries (one to three trips daily) than drag racing (never.) Steve put me in charge of solving the problem, so I ran with it. Pestered everyone I could think of. This included: Ted and Nancy - the wonderful owners of Motorcycle Stuffs; Ellsworth, owner of Ellsworth's Custom Cycles, and his "boys;" Al, the guy who mans T&K Cycles when owner Kenny is not around, and the amazingly knowledgable and kindly members of the About.com Motorcycle forum. Others who were helpful were the Jardine and Kawasaki folks themselves. At the bottom of this page you'll find them listed with contact numbers and links. Boiling down what the many folks I talked to said: Basically, I was told that since the Vulcan is such a sturdy little bike, parts just don't break very often, so there are not a lot of aftermarket parts out there. What there are, do not duplicate the OEM stuff, they change the bike to something else - like a dragster. Or, because the bike, though relatively small for a modern motorcycle, has something of a "big bike" Harleyesque style, when people do modify it, they try to make it more like a Harley - which frequently translates as "louder." So, as it turned out, the Jardines were probably the quietest aftermarket pipes available. Oh, NOOOO! Pass the ear plugs! The Goal My father had banned the bike from his home, because his neighbors complained when I rode up. I would cringe when riding into the gas station. We really wanted not to be embarassed to ride the bike through town. We wanted a lower pitch, a more mellow tone, and a generally quieter bike. The Solution To get what we wanted, the only option was to modify the Jardines. The Jardines have a relatively simple baffle set-up - Basically it looks like a cheese grater has been rolled into a cylinder, with the blades on the inside. The "grater" is about a foot long, a little over an inch in diameter, and has a thing that looks like a quarter bisecting it at the center. It opens out to an effective throat of almost two inches. I am more musician than mechanic. Steve is more mechanic than musician (though he is also an excellent Country Wester singer). But, amazingly enough my training in Hawaiian music does have some crossover into this particular area. When we make the `ohe hanu `ihu, the bamboo nose flute, we control the tone of the flute - its resonance, "warmth," and other intangible attributes - by carefully selecting the material and the inside diameter. We control the pitch of the flute - whether it is an "A," an "E," or another key - by choosing the inside length of the flute. We control the volume by adjusting the amount and speed of airflow. We decided to apply the same principals to the mufflers. I would create a set of baffles which could
be inserted into the existing ones to restrict them (reducing airflow to
lower volume), and extend them (lowering the pitch). The only reasonably
obtainable material which would stand up to the temperature and
vibration stresses is stainless steel, so there was no real choice in
material (so we had to hope for the best regarding tone). Materials used:
Using a #203 light duty welding tip, I cut several discs from the puka steel. I would use the four best. I also cut two 2" diameter discs, and two 3-1/2" by 4-1/2" wide sections from the puka steel.
The upper end of the sleeves have the puka steel discs braised on. The center puka is drilled to 1/2 inch. One washer is around the sleeve to set the depth it will slip into the existing baffle. At the lower end of the sleeve is the large disc. Outside of that is the other washer. The stainless collar is even with the surface of the outer washer. All parts are braised into place. I used a #204 light duty tip and 1/8" braising rod. The spacing was set to give an additional 1/2" of length to the effective baffle. That was the longest we could go and remain in the outer pipe of the muffler. Then it was time to insert the additional baffle. The existing holes through which the factory had rivited the original baffle were used. The new bafles were inserted and drilled in place. Stainless steel sheet metal screws were used rather than rivits. If there were problems, we wanted to be able to remove the new baffles.
A final wish and a prayer, and Steve put his modified mufflers on his
bike. Lei: "You put 'em on. It's your bike." Steve: "It'll be fine, Honey. I have confidence in you." Lei: "Great. That makes one of us."
Steve: "Looks just like what I wanted." Lei: "I love a happy customer. When you're ready to fire it up, I'll stand over there - just in case any shrapnel blows out." Steve: "They won't blow out. . . ."
". . . . . OK, where's the key?"
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We were actually pretty happy with our little modification. The bike runs cooler and is much quieter, though not quite as quiet as when it was new. At idle, the tone is something of a rapid, happy chuckle. The pitch is a bit lower than before the modification. A second, higher, overtone starts coming in around 4K rpm. It's not exactly what I was shooting for, but it's not unpleasant. It's actually rather musical. Rather appropriate, we think, for a bike that's ridden by a mechanic who plays with music, and a musician who plays with mechanics. |
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A Big Mahalo to:
Ellsworth's Custom Cycles Motorcycle Stuffs T&K Cycles Inc. - Custom bikes, parts & accessories for
Harleys Jardine Mufflers (I have to look up the link again) AND. . . . . . The Forum Family of About.com
Motorcycles! |
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I
put the rectangular sections through the sheet metal roller and then,
with a leather mallet, hammered them on a pipe form to make the
tube-like baffle inserts. Each was then cut in half, giving me four. I
would
choose the best two. (I'm still not that good a welder, so I wanted
spares!)
As I was also working (
