Buell XB12X Ulysses Performance Mod

Ever since I purchased my 08 XB12X from Glendale HD / Buell I noticed that there was a slight delay when getting on the throttle. I talked some other folks that had test rode them as well, including the new XT, who experienced the same issue. Still, the bike had tons of power so I really didn't think much of it and put over 6K miles on it.

After some talks with my Buell experts, Josh and Ernie, and some analysis of the service manual I discovered that the exhaust might be the problem. When the bike is cold the actuator in the exhaust system is closed off. Once the bike is up to temp it opens up a little, and when applying throttle it will open even more. I noticed that I had to bury the throttle in order to get the exhaust to open up.

I theorized that if I could force the actuator to stay in the open position the bike would respond better and I wouldn't need to buy an after market exhaust. After all, the bike has plenty of juice, I just need to get past the delay in power.

I disconnected the actuator cable from the regulator on top of the air box. The actuator is spring loaded so it failed into the open position. I thought to myself, "that was too easy." I started the bike up cold. Immediately I noticed the bike sounded more "Harley-Davidson" at idle. I grabbed throttle and wrenched down on it to discover there was no delay or sputtering (something that occurs when the Buell is cold)!

I rode around town for about 10 mins with a huge grin on my face. I had to get on the highway so I headed west towards Angeles Crest HWY. The sun was still up so I headed up the mountain. I was able to let the bike run lower in the RPM's and when I buried the throttle I got immediate response. I rode back home and was absolutely satisfied with my discovery.

More Power?

I am sure that the Drummer, SpecOps, and Jardine pipes will give you some extra power but I am not sure there will be such an extreme difference. Another thing to consider is your neighbors and local laws. If noise will land you in trouble you may want to try my mod before you buy an after market exhaust. You will see immediate improvement in power and response without causing or getting into trouble. Those of you in countries like Germany may want to consider this before anything else.

This cost me absolutely nothing to do (maybe 10 mins) and I am floored by the improvement. I am going to look into getting some Dyno tests done to show the differences. If anyone has any info on that please post a comment. I have never had one done and don't know what it entails.