Math can be tough sometimes, especially when it comes to counting, so we can understand the confusion surrounding the news that Erik Buell has recently been awarded a patent for a design that incorporates a motorcycle exhaust system inside the swingarm of the bike (now that’s some engineering). However we have the unpleasant responsibility of saying that this patent is not in fact owned by Erik Buell and Erik Buell Racing, as the filing date and patent assignee information were clearly over-looked by early reports on Buell’s patent.

While the patent was published on October 28, 2010, its was filed by Buell last year (April 24, 2010), well before Harley-Davidson closed the company, and while Erik Buell still worked as a Harley-Davidson employee. As such, the patent is assigned to the Buell Motorcycle Company, whose intellectual property is still owned by Harley-Davidson.

Despite the fact that Harley-Davidson gets to keep this patent under its divorce agreement with EBR, Buell’s design is pretty impressive. It might be an answer to a question that no one asked, but when you consider the difficulty in the goal, you have to appreciate the creativity in working up a solution.

In the patent Buell outlines a multiple stage exhaust system that sees a intermediate muffler acting as lower chin fairing (presumably containing a catalytic converter as well), which is attached directing to the down tubes from the header. The intermediate muffler then attaches to a flexible pipe which serves as the link to the pivoting swingarm.

Once inside the hollow swingarm, a perforated pipe disseminates the exhaust gas into the swingarm chamber(s), which in-turn serves as secondary muffler of sorts (the patent provides that this could serve as the only muffler in the design if found to be adequate). The swingarm design includes exit ports for the gas to escape from, as exhaust fumes fill the swingarm cavity.

Presumably Buell’s design would reduce the overall weight of the motorcycle, with only a marginal increase to a bike’s unsprung weight. Pretty clever if not wholly unnecessary, but it’s this sort of outside of the box thinking that made Buells so intriguing to their riders.

Read the full patent at Free Patents Online

  • Long Live Erik Buell.

  • BikePilot

    Somehow I don’t think EBR will miss that one too much.

  • Doctor Jelly

    Harley isn’t going to do anything with it so hopefully they let EBR develop the idea. I’d consider putting one on my 1125.

  • Blueduc

    This isn’t new- Confederate motorcycles has had this feature (although not nearly as eloquently) on the Hellcat for nearly a decade.

  • MikeD

    Meh, he’s done better. It looks like a doodle anyone with too much free time did while waiting for food.

  • Dude

    How exactly would this REDUCE unsprung weight? Surely it would increase it

  • Sean

    Im looking forward to his ashtray in the triple clamp design.

  • 76

    Cool on the “design” level and could allow for a very clean and integrated look. On the other hand I really dont know what it accomplishes on a engineering/performance level other than complexity in a swingarm. It seems to replace a silencer, a silencer weights very little compared to the amount of extra welds and walls needed to incorporate this function into a swingarm.

    Its like his single disc mega rotor. It reduces unsprung weight yet at the same time achieves the same as a stock wheel and worse than a aftermarket forged or mag dual coventional rotor setup because of the Moment of inertia (MoI) The increased weight towards the outside of the wheel is the cause. You would be better off with Mags and a aftermarket rotors. Again cool but not better

  • aaron

    umm… Imme anyone? over 60 years old and I’m sure there’s still some awesome vintage German tech that will be claimed as their own cutting edge design by American boutique bike builders…

    sarcasm aside, does anyone else find it ludicrous that harley davidson owns a patent to a stealth exhaust?

  • Other Sean

    Sean says:
    November 24, 2010 at 10:26 PM Im looking forward to his ashtray in the triple clamp design.

    I was hoping someone would capture the sentiment I was having trouble putting into words. And another Sean, to boot. Thanks for the laugh bud!

  • Nob

    What is this man on ? I want some ;-)

  • Aaron – thanks. A lot of people think Confederate were the originators of the exhaust in swingarm but they were preceded decades earlier.

    Dude- the article states, “Presumably Buell’s design would reduce the overall weight of the motorcycle, with only a marginal increase to a bike’s unsprung weight. ”

    Reduce vehicle weight? it seems an alternative front-end to the tele. is an area where a significant weight reduction could occur. It would be interesting to see what Erik Buell has brewing for alt. front ends.

    (James Parker’s design drops 22 lbs. off of a stock GSX-R)

  • aaron

    hoyt – the imme’s single sided front is still ripe for the picking (although gilera did build it briefly for the cx125)

  • irksome

    What the hell would HD do with non-’50s technology?

  • License the technology to another company.

  • Mike L.

    Technology? Is that what that is?

  • hoyt

    James Parker’s RADD front-end dropped 22 lbs. off of the GSX-R by eliminating much of the bulk of the aluminum spars and stout steering neck. This would be difficult for Buell’s fuel-in-frame approach.

    Mike L. – I would say it is innovation whether you’re a Buell fan or not. Japan & BMW have adopted some of Buell’s mass centralization tech. If the above doesn’t make it to production, it doesn’t mean that other ideas won’t come from this type of thinking.

  • akatsuki

    Hmm… if HD has it, then this is probably dead in the water since HD doesn’t actually care about innovation, unless you can find a way to make chrome shinier and even more expensive.

  • GeddyT

    Three infra-red temperature sensors: what, a couple of ounces each?
    Three servo operated flapper valves: one pound?

    A rear tire that’s ALWAYS the exact perfect temperature on both sides? Priceless.

    I was thinking a few years back of trying to patent a system just like this, but got lazy. Figured it was probably already done anyway (every other great idea I’ve had has been…). Also I noticed that MotoGP made a new rule to ban active tire temperature monitoring (or maybe it was WorldSBK, don’t remember).

    At any rate, route the hot exhaust gas through the swingarm and use valves to meter the hot gases to the left and right sides of the rear tire to keep both sides in the perfect temperature range for optimal grip (as measured by the IR sensors). If the track or road is one that keeps the tire hot (and evenly hot), close both valves to the tire and open the one on the back of the swingarm that routs the gas out the regular way. You’d just have to make sure that the logic knows to have the same total opening between the three valves so that exhaust restriction doesn’t fluctuate and mess with the power smoothness. So if the main valve is twice the size of each tire valve, left side valve is at 30% open, right side valve is 70% open, then the main valve would have to be 50% open. If left valve is open 50% and right valve is closed, main valve would have to be open 75%. If both side valves are wide open, main valve would be closed. You get the point.

    Seemed like the predictable rear grip and improved tire life would be worth the slight increase in unsprung weight. And figuring out a way to make it work on the front tire as well? That would be the holy grail!

  • steve_a

    The main advantage of this design is packaging: Trying to find a place to put a muffler on a streetbike is hard if you care about things like weight distribution, handling, and polar moment of inertia, particularly one with a wheelbase as short as a Buell’s. Also, modern mufflers are heavy, heavy . . . and if you can make a muffler share some structure with the swingarm, you are likely to be able to reduce overall machine weight. Also, this design works best for medium volume mufflers, such as would be required for a turbocharged large-displacement Twin or, say, a middleweight Triple. For the last bike, this design is as sweet as Sugar.