Of course those are expert riders on race prepped (read, good suspension, mildly massaged motors, with a little weight reduction thrown in).
My advice to you as a B group rider is to put the lap timer away and spend more time working with CR's. They don't call them crash timers without reason. Working fundamentals such as smooth throttle, steering & brake inputs, body posture, and lines will do more for you than chasing lap times.
Put good suspension (a penske out back and springs/emulators up front) and ride that thing. SV's are slower than the 600s/1000s, but not that much. At Road America (a 4 mile track with 3 straights) last year, there were only 3-4 bikes that were going faster than I was on my SV, and that was in the Intermediate group.
Get a lap timer, put it somewhere you can only check when you are not on track, and FORGET about judging your lap times against other people's lap times. Your lap time is about your performance, nobody else's. Having a lap timer will allow you to see your progression, nobody else's. Turning a 1:37 at RA is meaningless. Turning a lap 3 seconds faster than you did at the beginning of the day is something to be proud of. But it's got nothing to do with anybody else.
And this is THE MOST IMPORTANT PART: you won't always be faster than you were last time/this morning/yesterday. When that happens just take a deep breath and realize that you are riding a motorcycle on a race track, and it just doesn't get any better than that.