That's a decision only you can make Jean-Jacques. Some people have installed similar tires with a 74 load rating and claim no problems. The fallacy about using those claims to justify doing it yourself is that you are only going to hear from the people who claim they have no problems, if you follow what I'm saying.
The bike, or a car for that matter, is designed with a maximum weight rating that includes passengers, luggage, etc. that is called the GVWR, or gross vehicle weight rating. The tires are then specified to meet or exceed what is required to support that GVWR. In most cases there is a safety margin added because the manufacturers know that many people ignore the GVWR and overload their bikes or cars or trucks. You may say to yourself, well I only weigh 150 pounds and I never carry a passenger or luggage other than a jacket, so I don't need to worry about using the tire specified by the manufacturer. If you're willing to take that chance, it's not up to me or anyone else to tell you that you can't do that. I just point out in these threads what the manufacturer and tire company say is the minimum load rating they recommend. I've also been known to point out that the use of tires rated lower than what's required will also leave the owner of the bike on the hook if something bad does happen. The manufacturer and tire company won't be liable.
Anyhow, like I said, it's a decision I can't make for you. You may find that the tire designed for a lighter sport bike also won't wear as well as the tire designed for a heavyweight touring bike, and it may not be a great match with the stock front tire in terms of cornering grip, etc.. There is a lot involved in specifying tires other than just what will fit in the opening and on the rim. That's why they pay engineers to make those determinations and don't leave it up to just anyone.
Jerry