Yeah, the Japanese market 'Serow Mountain Trail 225' had discs front and rear. The XT225 that Yamaha marketed overseas, including in the States, came with a front disc and a rear drum. Why so? Obviously a marketing strategy of some sort that Yamaha settled on. Other than that your guess is as good as anyone's..

It's the "tubeless" rear wheel that's a big deal to me. Having a tubeless rear tire would have saved me tons of misery, grief, and pain. For some reason most of my flats were on the rear. It also shows, along with the 1986-1987 Honda Rebel 450, that had the same type of wheels front and rear, that tubeless wheels are totally feasible on an inexpensive bike.

I agree on the tubeless rear tire and wheel setup. That's why I'm going to try the tested and proven 'split inner tube' method to convert my stock XT225 wheels to tubeless. If that works as well as it's said to, then for next to nothing out of pocket (which I look for and appreciate) the days of carrying a spare tube and everything it takes to repair a flat tire will be no more for me.

I was going to work on that conversion this week, but roadblocks appeared and it'll be another week or so before I get to it. Leaving for the Valley tomorrow to help get my son's house in Mesa ready to sell. Be back mid-afternoon on Sunday. Then I need to assemble and install a Harbor Freight tire change machine with the motorcycle tire add-on. After that's done, with places to be and people to see on my early April to-do list, it's just a matter of finding time to fit the 'tubeless' conversion on my XT into the schedule. Once I do though I'll post photos of how it went and let you know what I think of it once it's done.

If for some reason or other it doesn't work, and I can't imagine what that would be, I can always put the tubes back in the XT's tires and roll like I've been rolling all along. It's sort of the old "nothing ventured, nothing gained" thing, so stay posted and I'll let you know how it goes..

I will be very interested to hear your thoughts after you do the conversion. I’ve never had a motorcycle flat, since most of my riding is on road, and I’ve never taken a motorcycle tire off the rim. I think I’d like to learn in my garage rather than on the side of the road.
The 5-riding-day Moab trip I’m doing at the end of May will probably put more stress and damage on my tires than all of my other riding combined, so a tire problem is much more likely. It would be great to just carry the sticky cords and a pump, not to mention the time saved by using the cords.
If you have a good experience I think I’ll give it a shot.

Back when I was younger and in good condition changing a motorcycle tire was no big deal. I learned to change them on a dirt bike before I was old enough to get a license. But now that I am old and disabled, things are different. I could still do it at home, in fact I recently put a new tire on the back of my XT, while it sat in my house, over a period of 2 days. My legs cramped up bad from sitting on the floor working on it. You wouldn't likely have that problem. I have an aftermarket centerstand on my XT, so having a way to hold the bike up while removing the wheel is not a big deal. It's being able to get the wheel off, get the tire off the wheel, replace the tube and get the tire back on the wheel, and the wheel back on the bike, all at one time, then being able to get back on the bike and ride out. If you are in good condition that would not be an issue. I've done it dozens of times out in the desert or in the forest over the past several decades.

Fortunately, tube type tires are much easier to get on and off the rim than tubeless tires, because they have a much thinner more flexible sidewall and bead. You do need to be careful not to damage the tube with tire tools, and make sure it is not pinched between the tire bead and rim when reinstalling it. It's 10 times easier if you use some kind of lubricant on the bead. I carry a spray bottle of tire mounting lube with me. You won't likely have to break the bead, by the time you realize you have a flat tire, the bead will already be broken. I don't have to deal with a bead lock, because I keep my tires inflated to 32 psi. If you run low pressures you will need the bead lock, at least in the rear.