it sounds like you may just have too much prop. Keep an eye on it and have your dealer swap you out props if your not getting 5000+ out of it.
If it's your prop, your power will be down significantly at 4500 rpm. You may gain 100 or so rpm after break in, but 400-500 would be a somewhat major expectation.
Also, just a thought, but raising the rev limiter to 5400 will just pull your motor out of the power band unless other mods are made also.
Steve, email me offline on how your trip was!!