Popping sound and lagging when riding

[saboulet]

So I went riding to the mountains this past Sunday with some friends and my bike handled nicely the entire way up there and during the ride.  It was only when we were on our way back South on 129 that my bike sounded like it was delaying for some reason while in 5th gear.  It almost sounded like it was a popping noise coming from the engine and even though I would be going a constant speed of about 65 mph, it would not be constant power.  It would sound like my bike was having trouble maintaining that speed.   

Anyone know of anything what's wrong or what I should do to try and fix this? 

Btw, I have a 2002 Ducati Monster 750sie. 

Thanks in advance!

[Duckintime]

elevation

[saboulet]

elevation

Ohhhh, that might be it.  Thanks for the help!