Stuart nicknamed the bike "Vinnylonglegs"
A motorbike bought in the north-east of England that has done 721,703 miles (1,161,468km) is to be auctioned.
Only having had one careful and loving owner, the 1955 Vincent Black Prince is expected to fetch at least £35,000.
Stuart Jenkinson, from Guisborough, bought the motorcycle in Newcastle and has modified it many times over the years.
He has also ridden it all over Europe as part of his own long distance touring company.
Bought in Newcastle in 1955 for £350 it was a top of the range model and Stuart nicknamed it "Vinnylonglegs".
Stuart said: "We didn't have a car, so it was used for going shopping, holidays and going to work and I had a 20-mile ride to work each day.
"For the sorts of distances, countries and roads that I was using it on for touring, it had certain short comings, so I modified it accordingly."
He improved the handling, the brakes, the electrical system and made the body more aerodynamic.
Stuart says it will be difficult to give the bike up
After leaving his teaching job, Stuart started a motorcycle touring business which took the bike all over Europe.
"It's got nearly three-quarters of a million miles on it [the clock] now and a good half of that has been running the tours."
'Bite the bullet'
If the bike had its own passport, it would be filled with stamps from countries such as France, Germany, Austria, Switzerland, Spain, Portugal, Norway, Sweden and Greece.
Stuart is now 83 and finds it a bit of struggle to turn the motorbike around and ride it: "That's no way of motorcycling, I don't think, and I've finally decided to bite the bullet and say goodbye to it.
"As any long term owner of a bike or car will understand, selling Vinnylonglegs after 56 years and almost three-quarters of a million miles is going to be a serious wrench.
"I'll just have to make do now with the memories of all our wonderful trips.
"I would like it to go to someone who's going to ride it and get it to the three-quarter of a million mark, it's capable of doing a million miles, I'm sure."
The bike will be auctioned at the International Motorcycle Show in Staffordshire on 24 April 2011 and has attracted a pre-sale estimate of £35,000 - £40,000.