Here's the official break-in chart from the RE Service Manual...translated into MPH. Wisdom dictates that you follow it just about to the letter. Running too fast, too long during break-in can result in several nasty occurrances, none of which you want to happen. Be easy on the bike during this period.
Break-in: First 500 Miles/800 Kms - Bullet
1st 50 Miles, < 30 MPH
50-500 Miles, Vary the engine/vehicle speed, avoiding any steady speed for long distances. Vehicle speed up to 37 to 40 MPH is permissible.
Avoid fast starts at wide open throttle. Drive slowly until engine warms up.
From 4th gear to 3rd gear - 24 MPH or less
From 3rd gear to 2nd gear - 18 MPH or less
From 2nd gear to 1st gear - 12 MPH or less
CAUTION: DO NOT EXCEED THE SPEED OF 37 to 43 MPH during 500 to 1000 Miles
GEAR CHANGE PROCEDURE AND SPEED DURING ACCELERATION:
From 1st Gear to 2nd Gear - 25 Kmph to 30 Kmph
From 2nd Gear to 3rd Gear - 35 Kmph to 40 Kmph
From 3rd Gear to 4th Gear - 45 Kmph to 50 Kmph
From 4th Gear to 5th Gear - 55 Kmph to 60 Kmph
DURING DECELERATION:
From 5th Gear to 4th Gear - 60 Kmph or less
From 4th Gear to 3rd Gear - 50 Kmph or less
From 3rd Gear to 2nd Gear - 30 Kmph or less
From 2nd Gear to 1st Gear - 20 Kmph or less
I didn't translate the gear change speeds to MPH as listening to the engine and having a feel for it running easily is the best way of telling when to change... only note well... do not lug the engine during break-in... doesn't pay to do so either after break-in...
Have fun, and enjoy the road and sights at lower speeds. One gets used to that during the break-in period. It's nice.