Exhaust Modification

[Poeman]

I am a real "Newby" with modifying bikes and was wondering if anyone could share any additional insight into changing the stock exhaust currently on my XS-11 to a stock Harley Fat-Boy exhaust. I saw a post with some info on it, but I could not find any final results or potential problems. I have an awsome bro-in-law who took the pipes off his Harley last year and is willing to help me put them on my XS-11. Any insight anyone could share would be greatly appreciated!

[TopCatGr58]

Hey Poeman,

Have you seen This Tech Tip ? Also, doing a search for fat boy mufflers would probably yield several threads here as well!
T.C.

[Poeman]

Hey T.C.,
Ya I saw that Tech Tip, but it sounded like he may have had some idling problems that I don't know if they were related to the exhaust modification or not. I just want to be certain I know what I am getting myself into.

I will do a few searches as you suggested tonight. Thanks for the input!

Poeman

[Dennyz]

The XS (and probably XJ) are tunned pretty well to their stock exhaust. If the stock exhaust is changed, one should not be surprised if a bit of carb tuning is needed.

[Poeman]

Thanks for the info, DZ. Maybe I should wait until next winter to change over so I don't wind up having the bike down longer and miss more riding time this summer as I am not certain how long it would take me to get the carbs properly readjusted. Thanks again for the response.

[Igotit4free]

Chuckle chuckle, sounds like thats some awesome "bro-in-law". I'm thinking that we will have no problems as long as we can find the guy that posted the modification and ask him all the right questions.

[Igotit4free]

Oh, hey, you realize this modification will also eliminate the crossover pipe and give you a true dual exhaust. I'm now almost certain that we will need to retune the carbs as it will definately effect the back pressure thus causing issues at idle and more importantly on deceleration. I dont think this is much of a problem but we can talk to Dane and have him come wave his magic wand (fingers) over it. We also need to find the missing or very well hiden port on the number two carb for the vacuum advance.

[Igotit4free]

might be a good idea to try to find a set of manufolds (OEM exhaust pipes) in a little better shape, to start with, so that we can build the entire thing without getting into a no going back situation.

[79XS11F]

I would not go down that road. These bikes are designed to be somewhat higher performance then a Harley or other large displacement twin. Once the exhaust crossover is removed you will loose all exhaust savaging and tuning will be "FUN". You will be farting around with the jetting for a while and likely never get it "just right" with non crossed over pipes on the bike. Even 4 into 2 pipes are not the best setup for these engines. The effect of exhaust scavenging is a rather important part of the bikes engine design to get good performance and fuel mileage.
Look for something that is more appropriate for this bike that gives you the look you like.
Rob

[Igotit4free]

point well taken. My experience level is limited to say the least. Thanks for the heads up. We just thought it would look and sound cool without thinking of the negative ramifications. Thaks again.