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-   -   A Call To All Great Exhaust Builders (http://www.xs11.com/forum/showthread.php?t=26440)

T99Ford 02-02-2010 12:30 PM

I would tend to agree with Cy. Remember that while engineers have performance in mind, it is not extreme performance. And, they are considering emissions, manufacturing and assembly costs, longevity, and rideability. I think it is for these reasons that the aftermarket offers the gains that it does. This is even more prevalent today, if one looks at modern sport bikes. The R6, for example, is reputed to show the largest aftermarket exhaust gains, and has the most restricted stock exhaust on the market. The aftermarket products improve performance tenfold over stock, not because the engineers can't design it, but because they are hamstrung by other (non-performance related) influences. Stock is rarely the best performer, but probably rather the best "all around" performer for those who don't know better. So just because the engineers designed it one way does not make it the best. It just makes it compliant with the engineer's requirements.
There have been major advances in exhaust technology in the 30 years post XS production, and I would venture that if modern engineering of exhaust were to be applied to an aftermarket exhaust for one of these bikes, one would see larger gains than any of the period aftermarket exhausts.
This is not denying that the Yamaha engineers knew what they were doing, but rather stating that the goals of the Yamaha engineer was not to optimize every aspect of performance. Mass production and having to make a bike anyone could ride limited the performance characteristics of their bike.
But this is great! Those like me who want to mod and then fool with specific characteristics of a modded bike can, and those who would rather jaunt around the countryside and not worry about their bike can do that as well!:D

daveyg 02-02-2010 12:49 PM

I understand that it makes sense that a 1,4;2,3 exhaust "should" work better, but many aftermarket exhausts even use the 1,2;3,4 method, I have on my shelf a titanium header for a GSX-R 1000, not a very cheap hunk of metal, yet it also uses the 1,2;3,4 Tri-Y design. I'm just saying that the costs vs benefits appear to lead toward the simpler design. One of the costs with our beloved 11 being ground clearance, another being oil filter access. Both of which would be extremely difficult to attain with a 1,4;2,3 system.

T99Ford 02-02-2010 12:57 PM

Ground clearance is a huge issue on these bikes for a 4-2-1. The stance of the bike does not allow for mounting like on a sport bike. There would need to be some engineering work there for sure.

daveyg 02-02-2010 12:57 PM

And in my opinion there are some very large flaws with the current model of R6, namely on exhaust, that could be easily fixed with "off highway use" parts. The greatest of all being the catalytic converter/pre muffler that sits under the bike, where the only muffler seen from outside is the tiny 6" long piece that acts merely as a glasspack. A 1,2;3,4 tri-Y design would obviously be more effective, but the US government doesnt care about hp...

cywelchjr 02-02-2010 01:05 PM


Originally Posted by daveyg (Post 255381)
I understand that it makes sense that a 1,4;2,3 exhaust "should" work better, but many aftermarket exhausts even use the 1,2;3,4 method, I have on my shelf a titanium header for a GSX-R 1000, not a very cheap hunk of metal, yet it also uses the 1,2;3,4 Tri-Y design. I'm just saying that the costs vs benefits appear to lead toward the simpler design. One of the costs with our beloved 11 being ground clearance, another being oil filter access. Both of which would be extremely difficult to attain with a 1,4;2,3 system.

Actually my Jardine system provides almost 0 interference with the oil filter or the oil pan for that matter. For that matter, as I understand it, they also achieved the same length on the pipes to the collectors for each cylinder which is also hard to achieve. I have to say I also love the sound of it, with it being a bit aggressive without being overly loud. I can still blip the throttle and set off car alarms with it though. :D

Pat Kelly 02-02-2010 05:14 PM

My Jardine 'spagetti' pipes are quieter than the stock pipes. Ground clearance is fine but lean angle is less as the system is wider than stock.
My RC Eng 4 into 1 is tunable for loudness and back-pressure. Lean angle is no issue but ground clearance is (bottom 2 pipes are now 'D' shaped). This system was designed for track use, not real-world. I have mulled the idea of making a 'Y' pipe from the collector to run 2 (tuneable SuperTrapp) mufflers for astetic reasons. The bike just looks naked on the left side with no muffler.
Both systems retain the centerstand and don't require removal for acessing the oil filter.

Mashermoto 02-03-2010 05:15 PM

Pat, I agree that the XS1100 looks naked on the left side with out a muffler. With a 4-2-1 system or 4-1 system, I don't understand why every manufacturer's systems exit to the right :confused: I guess when they designed their systems, they checked the file to see what they did for the last bike built and it was to exit to the right :D

I called MAC yesterday and they actually returned my call :eek: They are not going to start production on their 4-2 taper tip system for 6 more weeks :( They are also not open to any of our suggestions for a new exhaust design. Because they are the only US supplier of exhaust systems for our bikes, any new design has to be home grown.

IMHO, I think the reasonable solution is a 4-2 system with shorty reverse cone mufflers that extend out half way between the rear axle and rear foot pegs. It would look good, sound good, should perform reasonably well, provide easy access to the oil filter, allow oil coolers, and might allow center stand retention :cool:

Now then...who is going to build it :rolleyes:

Pat Kelly 02-05-2010 09:17 AM

Possible reason for right-side exit is for flat-trackers. If it only comes out one side have one part number for everyone.

bikerphil 02-05-2010 11:26 AM

Another theory. The right side exhaust exit doesn't interefere with the side stand.

Mathh 02-05-2010 11:51 AM

I think it has something to do with the mess the chaindrive on normal bikes makes. I know there were some left side models in those days,merely used by side car owners..

DGXSER 02-05-2010 11:56 AM

Perhaps it started with circle track racing and the need for left side ground clearnace but none on the right?

Mashermoto 02-05-2010 05:16 PM

Well...with MAC now out of the picture...this is my next attempt to get a system on this bike :o


There was only one on Ebay from the seller who actually lowered his buy it now price for me :) So I'm going to use this as a test case...if it works out I'll buy another one for the other side.


I'm going to attempt to use these old MAC 4-2 header with the SuperTrapp 443-2217 universal mufflers.


I've got this problem with one side...the gasket flange is broke :eek: I'm not real sure how I'm going to work that out.


It's going to be a close fit for the out side can to clear the foot peg mounting bracket. The muffler shown is 3 inch diameter and the SuperTrapp is 3.5 inches before it tapers up to 4 inch. However, it looks like the 17 inch length will extend the exhaust end right between the rear axle and foot peg just like I wanted :cool:

One down side is that I will need to make the headers flat black where as I wanted an all chrome system. But I might actually like the black headers mounted with the brushed stainless steel mufflers more than I think :rolleyes:

Chroming the headers is cost prohibitive and probably wouldn't go well with the SS mufflers :o

T99Ford 02-05-2010 09:56 PM

Good luck with that plan! Will be watching to see how that can looks, as I have thought about getting rid of this Mac one. I hope it works for you this time. I have black headers on mine, to no detriment to the looks. I do have to touch them up from rock ships from time to time:


BTW, is your rear fender mounted all the way, or are you working with it? It just looks a little "flat", like it could stick out a little more. But it might just be the angle of the photo, too. I was just comparing it against mine, which is still mounted stock:


Nice looking bike! I like your use of colors a lot!

Ken Talbot 02-05-2010 10:57 PM

Here's a post from a few years back - Denny Zander's home-built exhaust system:


Mashermoto 02-06-2010 09:02 PM


I've seen your bike before and I gotta say that looking over yours again makes me warm up to the black header option even more :cool: I think I will be happy with it :)

Also, the fender pictured is in the OEM mounting position. That's just the way a 78 Standard mounts :rolleyes:


I tried something like Denny's setup.


I bought a couple of Kawasaki ZX10R mufflers on Ebay and attempted to mount them on each side using the MAC 4-2 header shown in the above pictures.


I ran into some of the same problems with the rear pegs as Denny experienced. The location is great for rear passenger comfort, but makes anything but a below mount muffler difficult to pull off. At least without major modifications. Sport bikes get away with it because the rear pegs are mounted so much higher. So I moved the mufflers way back and tilted them upwards. Even so, once I got a pipe built to bridge the header to the muffler, the exhaust pipe would still be in the way of someone with an average to large foot.

I abandoned the project after taking an honest look at the design and felt like I just couldn't live with it. The pipe that bridged the header to the muffler just looked way out of place. It looked like I was trying too hard to make it work. The other problem is that there were some tough angles to cut to make the pipe fit up. Even with the aid of a chop saw, I was wasting expensive mandrel bend pipe. Things got worse when I went to welding the pieces together :o

I've floated this balloon a few times now and will shamelessly do it again...somebody needs to step up and build a decent system for our bikes and put it out here for the XS1100 community. The fat cat companies are not up to the task :(

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