View Full Version : dual exhaust

08-05-2010, 07:30 AM
Am I the only one building a true dual angled Japan style exhaust?

08-05-2010, 07:36 AM

08-05-2010, 08:39 AM
Yes. Yes you are. You know that is an all around loss compared to what your bike came with, right?

08-05-2010, 08:59 AM
There have been a couple of others do the same, one over in europe somewhere, the other over here in the US.

08-05-2010, 11:08 AM
errr why? Even most Jap bikes have gotten away from that.

08-05-2010, 11:51 AM
Just a guess here, I'll bet $$ it loses a lot of power. Especially up top, possibly as much as 10-15 hp. I assume you put it on a dyno prior to doing the new exhaust.

08-05-2010, 03:15 PM
even on cars it is proven to make more power by connecting both banks of the motor and equalizes pressure on both sides. Harley tried this on their sportster engines and I think a couple other models back in the day with their drag pipe design and thats why they went to that goofy looking pipe that goes straight across the side of the engine connecting both banks. Definitely gona lose power. talk to any bike builder and they will tell you that a 2 into 1 header is even better then straight up drag pipes. Hope all goes well for you

08-05-2010, 03:23 PM
Sounds cool Blakehorton83.Please let us know if you feel a gain,or loss.Totally different engine then the harley engine.Keep up the good work

08-05-2010, 06:21 PM
Almost no loss! -5ft/lbs same HP. Crossover section . Still pulls wheelies. Slightly less backpressure than stock. Here's the big reveal. http://m.flickr.com/photo.gne?id=4864037645&s=47847832&sig=b802730073f98d5ada6545d6fa8596d0&time=1281053627

08-05-2010, 06:23 PM
This also solves the heat issues with stock exhaust

08-05-2010, 06:44 PM
Not "japanese" style, but a dual can if you hadn't seen it. At least 16 hp gain, 13 ft/lbs more torque over stock. Stock was 122 hp, 69 ft/lbs. It's loud to most people though.


08-05-2010, 07:57 PM
What ever floats your boat i guess.[confused]

08-05-2010, 08:18 PM
I find it hard to believe that a short freeflowing exhaust would create more torque. BTW I have not tuned yet. Just two passes on dyno.I guess I just like having the bike the same width front toback. I am working on two other mods. An airbox with valves that open under negative pressure and stay closed during positive, and a ram air scoop under the fairing. Will have drawings and progress pics soon.

08-05-2010, 11:59 PM
Direct from the exhaust shootout as performed by American Sport Bike and JT&S Performance.

This was the 4th place pipe for hp, 3rd place for torque. Almost 17 hp more, 13 ft/lbs of torque. Keep in mind, this wasn't the winner, it was my original prototype that was abused for maybe 3000 miles prior to the test. One of the other pipes I sent in took the top spot for hp and torque, but the spread from 1st to 4th was .7 hp and .6 ft/lbs torque, so it's a pretty close deal. All the rest were 5 hp lower or more. This was just the stock vs. race ecm (untuned) vs. race ecm programmed for 13:1 a/f mix. I would imagine it will make more hp and torque.
Of course, I'm just a "hillbilly" and "shade tree mechanic" so I don't know what I'm doing.

Enjoy the tinkering with it, more air will help it some. I haven't modded my airbox yet, I'm hoping to get my hands on the RR airbox to play with.

BTW, if anyone tells you that you can't get 15+ hp and 10-12 ft/lbs more torque from adding an exhaust pipe to the 1125, you can let them know that you _can_ get it. 4 pipes in the shootout did exactly that, none were "tuned" for max performance and they'll all make even more power than what was posted.


08-07-2010, 07:33 AM
New pic with heat wrap. Still haven't painted the mufflers.( red or black?)

08-07-2010, 05:00 PM
Im not concerned with top speed, just launch power and torque

delta one
08-07-2010, 09:00 PM
are you holding those cans up with sign posts?

before you consider selling the setup (per your other thread) you should get some brackets made up

08-07-2010, 09:18 PM
If you meant the one I posted, that was prior to fitting the brackets to it. It was just a test fit to see what it looked like on the bike.

Off the bike, fully polished and ready to go.


08-07-2010, 09:22 PM
No offense man, but if you want that type of exhaust just buy the Japanese bike. Erik Buell didn't have the exhaust underneath for looks. Your just ****ting on the bike's Mass centralization.

08-07-2010, 09:32 PM
I like the duel look. I dont like the jap looking up the side pipe. It really takes away from its true disign.

delta one
08-07-2010, 10:01 PM
no not yours D
to be honest your dual (RT-4?) is IMO one of the best looking setups for the 1125, it looks like a sexier version of the XB D&D
the only other one that I like is the free spirits twin design (any of the 3 setups) but at a price WAY higher than yours I could never justify it.

on the flicker page blakehorton83 posted a link to it looks like there is about 2 feet of sign post running from the pass peg mounts to just shy of the blinkers. in one picture with header wrap all the way to the cans the posts are red.

you should get a machinist to mill you some brackets that you can install further down the tail section, maybe that mount to the sub frame inside the belly pan (obviously drilling/cutting will be required) it will probably provide a much cleaner look and look much less cobbled together.

delta one
08-07-2010, 10:42 PM
I should also add that the free spirits exhaust does not have dyno figures available. (much less video clips

the only thing that sucks about adding side or under tail exhaust to a bike that wasn't designed with it in mind is the huge arc the pipe needs to make around the swing arm. it never looks as natural or has any aesthetic flow to it.

but still gotta give you some props for making the bike your own

08-09-2010, 09:11 PM
To clarify: the brackets are temp till my machinist finishes. The billet alum ones. Also there's no arc. The brackets are 15". The hangers are all designed with vibration bushings. The upward sections will have alum heat shields as well as a shield that runs the entire length of the horizontal to keep heat off the engine. I started this whole mod because I never have passenger so I removed the rear pegs, but that left a huge ugly gap under the fender. I think it looks better than stock not to mention it sounds great and the engine runs cooler now. BTW what programmer should I get?

08-09-2010, 09:13 PM
Decided not to sell. Besides I'm the only one that thinks it looks cool.

Father of an ERA
09-05-2010, 03:38 AM
I think it looks pretty cool as well. My only issue is that the pipes look too small wrapping around the motor but that is just my opinion. Don't let any naysayers make you think any different. If you like the look and are obviously willing to put in the work, than its your bike and that's all that matters! Does the added weight to the sides of the bike make it handle any differently?

Father of an ERA
09-05-2010, 03:41 AM
I have to say that I really like D-adam's exhaust designs as well. The two of you are what ridding Buells is all about. Individual expressions, form, function, personality on 2 wheels. Keep up the great work!!!

11-07-2010, 08:54 PM
I got tired of wobbly wheelies so I took that **** off. I built an new exhaust that has longer downpipes and collects into a single 2 1/2" straight pipe (with hidden baffles inside) pics to come tomorrow. New top speed 171mph!

11-08-2010, 09:28 PM