This is a topic for design nerds, Thunderheader owners need not apply. :-0

What's the rationale behind the factory end caps on stock mufflers, I'm trying to work it out.

I'm in the process of customizing an RB Racing pipe, removing the vulgar balony slashcut to the side and looking to replace it with a standard H-D one to make a kind of "sleeper" pipe. Coincidentally, both their main canisters are the same OD. The RB is, obviously, a lot emptier and free flowing.

On most older models, H-D used their more subtle slashcut with the bottom side sticking out further. On some, the 2017 Street Glide being one, they use put the slashcut to the top, see below. (On others, like the 2-into-1 Street Glides, they use just a plain taper).

I think I get that the older design from a visual perspective. The line follows the line of the saddlebags nicely. But from a functional point of view, it sucks because by sticking out more, like an underbitten jaw, it catches and fills with rain, and then rusts. Bad end.

And there's another functional benefit when it comes to back up to sidewalks too. If you've got a slashcut to the bottom, the tip is going to hit first and damage. Rust again.

I don't imagine many folk will follow this or have an interest in it, but the H-D design is actually surprisingly subtle and elegant. It's not just a straight tube with a cone on the end. It gradually tapers towards the end cone before tipping in.

Of course, perhaps this discussion also only matters to those of us to live and ride in places it rains but I've been looking at used pipes where they've suffered in this way!

The RB is older and had picked up some pitting in the chrome on the underside, I'm guessing from sand/gravel spray, and beneath the heat shield. Surprising once you remove it, how much it eats into the steel even though it still "looks" OK on the outside.

It seems the 2017 have all moved to 'top downs'. Did they have some straight cut tap ends for a few years too?

Visually, I like the 'bottoms up' but functionally 'top downs' win. The straight cuts look a bit old, like FXR/Sportster pipes. The worst have to be the round ends they used with the heavy catalyst pipes, which also come in a 4". They are not even in the contending.

What was going on here, H-D just ekeing the parts bin out by flipping the pipes for another year, or some kind of thought?

 

Interesting points, and I've had similar observations and thoughts about the "slash" design. Since the SE Street Cannons can have the end cap on slash-up or slash-down, I've noticed that most that have them in this area have them installed slash-up. The lines follow the bags perfectly, but I personally don't like the look.

 

The more ways they have for you to spend money on different pipes and stuff, the more money they make.

Kinda suspect it's nothing more than that.

 

Thank you for the reasonable responses. I was, of course, putting on my best art critic accent. Here's where I got so far.

For me, there's no need to spend more than $50 for a pair of stock mufflers, you can pick some up from $10 to free depending on how many friends you have. I guess dumpsters behind factory shops are full of them. It's criminal really, we treat them like single use plastic food wrappers. H-D should sell their bikes with dummies on them.

We tend to forget that they also probably spent a 6 figure number on the aesthetic design of the stock pipes alone, and my guess a many 7 figured number for performance versus the EPA, and more for the tooling.

I was impressed when I discovered the subtle curve. It must have been mocked up in clay, then hand beaten out in metal, argued over in committee by product designers and managerment, and then add on the cost of tooling for production. The tail pipe has welded up longitudinally and polished out before chroming, probably by hand. I've not found where all the welds are yet. Of course, there is zero direct escape for gases. That hole at the end is fake.

For a while I thought it was blanked out but there are a series of perforation, about 1" wide, that makes the gases have to double back on themselves and pass through thick asbestos-like insulation material. About a 12" chamber worth of it. The gases aren't going straight along the pipe at all but hitting walls head on and doing about 4 x 90° turns, may be more.

Set that against the RB Racing which is a 4" straight and pretty much empty pipe, with a 45° angle cut at the end.

 

Oh, for anyone equally into interior design, that flooring really isn't that yellow either. Both pipes de-chromed.

 

Well, they've got to meet the EPA & DOT requirements, so they can't quite do that.

But look at how they sell the bikes. They sell them complete and at a maximum price. Then promptly up-sell you on pipes, bars, levers, floorboards, etc. It's a huge money maker for them. Many a rider proudly scraps things off their brand new bike before they even take posession of it. To the tune of thousands of dollars many times.

Harley is very good at making things look good on their bikes. Probably the best of any of the bike manufacturers. Customizing your bike is what it's all about with the Harley line-up.

So it's not at all surprising to me that they have many different pipes, bars, seats, levers, etc, all of them looking good and being well made, just for you to buy from them, at a healthy profit.

 

Couldn't agree more, foxtrapper...I've come to the opinion that Harley sells low margin motorcycles in order to create a market for high margin parts, accessories, clothing, and labor.

 

Sticking with the emissions side of things, it's a wonder some environmental group has not come down on H-D for doing so, as much of it is thru factory shops.

Then include into the equation how much energy/pollution/resources/labor/transport goes into making a stock pair of pipes only for them to never leave the showroom.

It's insanely wasteful.

At least on their own stuff they could do 'build to order', not 'buy then strip then buy again and dump'.

 

I saw/rode my 1st Honda back in the early '60's. Soon the market was flooded with well made, inexpensive Honda motorcycles. It was, a somewhat common, thought that Honda then activated a marketing ploy of doubling the price of parts.

 

I put the stockers back on mine and took off the V & H slip-ons. I LOVE it. Quiet touring.