I've got an 08 SD with around 6k miles on it. Bought it used for a steal a couple months ago. Since I've gotten it, I've yanked the air box and replaced it with some Uni pod filters, installed the shorter RC8 stacks, removed evap can and SAS, installed Yoshi exhaust and PCV. I took the bike to a dyno to get mapped last weekend and the dyno showed max HP at 103 after mapping. That just seems really low to me. I've been browsing the forums looking at some of the dyno charts that folks have been kind enough to post, and everyone else is up around the 120+ HP mark. Is there something I'm missing? Did one of the mods I did kill horsepower gains or is there something up with my engine that needs some work?

Does it run better after the mods? Was the air/fuel ratios monitored through the rev range?
From my thoughts, I believe that quite a few dyno charts we have seen are tickling the edges of reality and may be as erroneous as your under inflated number. 103 is much closer to reality than 121. I would ride it a bit and see if you are not happy with ?103? horsepower.
Where do you live?

I'm in the US in Georgia. The guy who did the tuning was the owner of a place called the DucShop.
I'd say it definitely runs better with the mods. The throttle response is a lot better and it feels a lot smoother. Gone is the hesitation when I grab a handful of throttle.

I'm pretty sure the air/fuel ratio was monitored through the rev range. Air/fuel was actually what I was after since I had no idea where the bike was at after the airbox and exhaust changes. The guy who did the map said that the bike was super rich all the way through and that he straightened out the air/fuel curve. The graph that he showed me that had the before and after air/fuel showed all the way through, but I'm rather new to mapping/dyno runs so I might have read the graph wrong.

If you like the power and it wheelies, what else more is there?
Enjoy, you got a powerfully fun motorcycle under you.

103 is a low figure but that figure depends on the dyno setup also. Optimistic dyno's are the norm so customers go home in the knowledge that they spent the money at the right place and can boast at the counter of the local pub.
Conservative dyno's are found in proper race tuners hang outs where figures are les important than proper performance.

Anyway 103 is a bit very conservative. Do you still have the second butterflies and shafts in place?
Also ask the dyno operator what corrections he dailed in the setup and what air-fuel ratio he used Dynojet recommends 13.2.
Is the SAS disconnected and how did they measured the air fuel ratio? Did you or the operator opened the O2 sensor holes to fit the wideband sensors?