Welcome to our forum.
I have looked at your blog and I love your enthusiasm. The bike in the living room picture is to die for. Who hasn’t wished to do that?
Chrislwg on our website has done Big Bore to his twin. Took it to 865cc with other mods such as twin spark plugs and oil cooler amongst others. He bought his twin new in 1976 and I believe can now boast over 100,000 miles.
Michael from the German website z750twin.de is currently in the process of producing an even bigger bore size. I am sure he will be on here shortly to help guide you.
Enjoy the site and please keep us updated with your progress and feel free to ask away and contribute.