Slip-on mufflers on Sportster : with or without cross-over tube ?

Hi everyone !
Nice to join your forum !

I'm getting prepared to offer my '06 carb. Sportster 1200 Low a Stage I. Right ?

- Stock Air filter will be changed for a Screaming Eagle for XL '04 & later one.
- Carb will be rejetted with to the CV performance kit
- Stock mufflers will be...

...this is where the problems begin for me. And this is where you guys may give precious advice about the necessity (or not) to keep the cross-over tube.

You know SAMSON exhausts ?
I asked about their mufflers for my Sports :
- I have a 2006 Sportster (2004-2006 carburetor family) and would like to change the stock mufflers for : "Slip-on Muffler Cannon with end cap". Are they compatible with the hidden cross-over behind the stock mufflers. Do they have the necessary holes to connect ?
SAMSON : 'Our mufflers do not use the crossover tube.'
- Then I asked :
If the mufflers DO NOT use the crossover tube, how do you allow gaz to mix in the exhaust ? On a 2004-2006 Sporster, the gaz coming from the pipes pass through the crossover tube and through the mufflers simultaneously because the first are directly connected to the latter (and no more to the pipes in front of the cylinders as it used to be on earlier models).
At SAMSON, you certainly know well how important it is to allow the exhaust gaz to mix before being released outside... How come you do not use the crossover tube ? What other system do you use then ?
SAMSON : 'On a free flowing exhaust there is no need for a vent tube as that is what the crossover tube is. The crossover tube should be called a pressure release tube because the stock system is very restricted. '

An official HD reseller told me same thing here. You can leave / take it away, same thing.

But on the other hand, I read everywhere that 2 in 1 exhaust are way much better. So, they use the principle of mixing exhaust gaz.

So ? Who's right out there ?

As I've read before, choosing the right mufflers can be tricky. But a buck is a buck and I don't want to waste any into a wrong choice.

So, should I go for those SAMSON mufflers ?

Many many thanks in advance to you all ! - Olybee

1st thing is that the crossover on 2004-up Sportsters is also a mounting bracket which you must have, unless you fabricate some other mounting setup. That is due to the frame & engine mounting change - thru 2003, the Sportster unit construction engine/trans was solidly mounted in the frame & is actually a structural member. In 2004, H-D went to a rubber-mount setup, the frame is larger & heavier & the crossover was moved from right under the carb to under the bike, where it serves as a mount for the exhaust.

2nd, the crossover tube is worth 5-8 HP & is even more important in the lower rpm range. Everybody (myself included) hates the looks of the crossover on the 1969-2003 models, but since it's been moved so you don't see it anymore, there's no reason to remove it.

3rd, the crossover is NOT a "vent tube" & doesn't have anything to do with "exhaust mixing" - it has everything to do with "reversion" - the sound & pressure waves that go back up the pipes. I will run out of space here before I can fully explain what reversion is & how it affects the engine, but especially with the W grind cams your bike came with, which have more "overlap" than the previous D grind, removing the crossover & thereby multiplying the effects of reversion will make the engine harder to tune & it won't run as well in the lower rpm range.

Last, as proven on the dyno, the track, the highway & the street so many times it's not a matter of argument, the BEST street/road exhaust you can put on a Sportster is stock pipes, WITH crossover & quality slip-ons like Cycle Shack, KromeWerks, etc. Samson is not on that list.

check out this site they will make your stock pipes better.
American Custom - Exhaust mufflers for your Harley Davidson Motorcycle - Home page

Your new here Oly and welcome, as far as anything sporster Art is the man!!!

I've also been told even for my big twin best tuning set up is stock pipes and good slip-ons. Also HD and Art have been doing pipes for a long time.

(Might just be a rumor but ART_NJr helped build the first harley ever made)

I'm not THAT old :roflmao::roflmao::roflmao:

But I did have a hand in building the 1st naturally-aspirated Sportster to break 180 mph, running gasoline & with no aerodynamic bodywork or nitrous oxide.

Hi everyone (shhht, you're still sleeping while I write those lines, so no shouting),

First of all a huge Thank you !

You're just fantastic and remarkably knowledgeable too ! Art, your science impresses me ! There's a French guy (Laurent Blasco) here in Europe who wrote 2 books on customizing the Harley but he doesn't go into such detail about the '04 Sports as you do...

So your answers go beyond my expectations really !!

Taking into account what you've said, I know I should take slip-ons that connect to the cross-over tube. I've seen a nice pair of Straightshots from Vance&Hines on eBay but the seller would not ship them internationally... too bad.

This link to American Custom looks very nice indeed !! I'll investigate this. Would you recommend sending the original pipes for a modification ?

Has anyone of you chosen this option and could tell me about his impressions ?

Again many many thanks and hope to read you soon ! - Oly

I wouldn't 'cause there's nothing wrong with 'em - all you really need is a quality set of slip-ons for a 2004-2006 model Sportster (designed to accept the stock crossover). And while the V&H pipes look / sound good & are quite popular, the stock pipes with slip-ons like Cycle Shack actually perform better.

Several catalog outfits ship overseas (I'm pretty sure J&P Cycles does) & the local independent shop I deal with ships overseas fairly often (Europe, Australia, Indonesia), so getting slip-ons shipped if you can't get 'em locally shouldn't be a problem.

Art, I'm not sure to have understood your point ...
- On one hand you say : "the BEST street/road exhaust you can put on a Sportster is stock pipes, WITH crossover & quality slip-ons like Cycle Shack, KromeWerks"
- On the other hand, all American Custom does is sell new (or modify your) stock pipes with interchangeable baffles, so they follow your word when you say 'the BEST exhaust is stock' and they allow to keep crossover while offering options to chose between different baffles.
Is this a 'poor' solution or is it OK according to you ?

My only doubt is about 'easily changing baffles on-the-roadside' ... this would request to tune the carb to balance air/gaz mixture (richness) no ?
Maybe that's why you recommend going for simpler solution like Khrome Werks or Cycle Shack...

You see, I was seduced by the idea of buying stock-looking-like mufflers with the Tone-flex system they provide at American Custom... so that's why I was asking about your opinion.

Mmmmh, I know, I have a habit of making things more complex than they actually look...

Hem... I went to have a look on the very-user-friendly J&P Cycles website.

Made me even more confused ...

I saw the CycleShack tappered mufflers (2" diameter).
I saw the Khrome Werks ones (2 1/2" diameter)
I even saw Khrome Werks mufflers with 3" diameter...

I don't know the diameter of stock mufflers (2 1/2" I sould guess ).
But if I've understood you well, Art, the idea is to get mufflers as close as original ones (outside the 'tappered' shape which is only a matter of personal taste).

So I guess I should forget about the 3" ones no ?

Sorry to spam you with my questions :gah:
But you know, it's always the same.
The more you start understanding, the more you see potential problems... until you make a choice knowing what you take and why you take it... getting closer no ?

I'll leave for now, letting you answer my existential questions :witsend: - Oly

The external diameter & style; tapered, "slash cut", etc. is a matter of personal choice. If the type you like the best is designed to fit your bike without modifications, the inlet diameter will "slip on" the stock headpipe just fine & the crossover will mount up properly too. The larger external diameter styles just have a bigger baffle inside & the overall performance level is nearly identical from one style to another.

I don't see anything wrong with it if that's what you want.

A baffle change shouldn't throw the carb off enough to worry about, but taking the baffles out altogether would.

That's one of those, "If it ain't broke don't fix it" deals - that type slip-on has been around for many, many years & works great.

If you want the stock look, better performance, but not much louder than stock, just get a hole-saw that'll slide down inside the mufflers, an extension for your drill & drill the center plate out. The baffle itself still works & I've got a set of drilled-out stock mufflers on the 2000 model Sportster. The sound level is so close to stock you can hardly tell the difference @ idle & running around town. It's louder than stock @ full throttle & out on the highway, but not much & certainly not as loud as SE I slip-ons (Cycle Shack style) I've also got.

With the drilled stockers on, the bike will "nose over" on the very top end, as even with the block-off plate removed, the flow still isn't as good as with the SE's, but in normal riding, there's no real difference in performance. It's just a matter of personal preference as to the appearance & sound level - personally I like the "baloney-cut" SE slip-ons better, but the drilled stockers are handy if noise ordinances or rousing your neighbors is a concern.

Art,

Thank you soooo much taking the time to answer my loooong questions !

I emailed 'Amercian Custom' who offer to modify stock mufflers, but they currently don't send overseas... too bad but OK, I'll go for a simpler and more reliable solution (Cycle Shack mufflers e.g.) as you very well explained !

Well, let me wish you all a very happy and prosperous New Year and may you keep health and joy throughout 2010 !

I'll keep in touch and let you know about my work on this fantastic bike !

Thanks again ! OLY

Hi Olybee, Art has given good advice
The crossover tube will give your Sporty exhaust system the needed volume. Look at a Buell....muffler looks like it came off a Lincoln, lots of pipe too. Keep your crossover and enjoy the extra HP in the lower RPM range.

Stock mufflers can be modified easily..
Cut the last 3" off your stock mufflers, tape around the muffler where you will be cutting, and use a fine tooth hacksaw.

When you have cut through the chrome outer part of the muffler, you will then be able to twist the inner pipe and a lot of the baffle material will come out with it. You may need to use a pipe wrench to twist the guts out of the muffler. Don't scratch your chrome!

You will now have an empty muffler can....
A muffler shop will be able to stretch a piece of exhaust pipe to fit the inside flange in the empty exhaust can, and stretch the pipe to fit the inside diameter of your now shorter muffler. You now have a larger exit hole in your muffler. A small bolt will hold the 'new' muffler guts in place.

You will be able to experiment with a variety of baffle designs, or straight?

I have modified a number of stock mufflers this way, and had the use of a dyno to see how they worked. You will be able to tune your torque curve

Plus they sound nasty!........Good Luck