Kyle Busch received a tribute in the middle of the Indy 500 Sunday ... with the crowd falling silent out of respect for him during lap 18 -- a nod to his former number. Check out the clip ... racers turn out of corner 4 on Lap 17 -- and, as they pass the scoring pylon, a picture of Kyle Busch "1985-2026" flashes on a screen at the venue. The Indy 500 crowd -- usually a raucous bunch -- falls into a subdued silence ... while pit crew members can be seen standing at attention. Dr. Chris Brown