[Lord-Blueberry]

Well, you got part of the equation there. Is 10 AFR the max of the sensor? Looks like you do not have enough fuel.

 

[Lord-Blueberry]

Yep, sorry I am dumb. Looks like it is either choking out or air, or it is fighting against exhaust gases?

I have seen powerloss with old/broken db killers, but not as severe as this.

IMO these are the things to check first. Since you have it on the dyno, does it change when you open up the airbox? Can you easily swap the exhaust which you know works as intended?

What's the bike's history? Since when did it lose power? If everything else is stock, then you are either looking at a broken production bike or you screwed something up during your air flap mod.

 

[Lord-Blueberry]

At 78hp it has to be something substantial. Like dead rats in the airbox or something. I can't imagine a broken servo can do this. My wild guess would be a molten/blocked cat. But again the low mileage...


If you find out, can you post it?

 

[Lord-Blueberry]

Wow, I'd never thought the exhaust butterfly would be that extreme. Good to know.