Hi Evelyn
.....and sorry I dd not welcome you to the forum when I responded to my first post, - WELCOME :hello2:
Lets talk indicated speeds, remembering the 400 speedo reads approx 6% fast.
The maximum speed of your Burger depends upon a number of factors, not least the all up weight and accessories but also the condition of the machine (tune) and importantly - belt wear.
I am 196 pounds and when riding with a stock screen on an English summer day would get up to a speed of 95 very easily. With a following wind and a downhill gradient I guess an indicated 100 is achievable if you persist.
The Burger is very happy at an indicated 80 or 85 mph. There is no vibration as such - just the sweet signature you expect from a single thumper. I am also of the school that an engine needs to work - and should be designed for it! If you are doing this for an extended distance it would be kind of prudent to check your oil level at say, each (or alternate) fuel stop.
Of course, if you have accessorised (large screen + huge top box) then this will affect this performance, as will carrying a pillion.
The short answer is the 400 will do what you ask no problemo, however the Lardy will do it in a more relaxed fashion and with more in reserve, but then again - so would a Dodge Viper! :wink: