Hello! I’d stay away from ECU flashes and such, doing things like that tend to come with their own problems sadly if it aint broke don’t try fix it ;). The chain is a must, you wouldn’t go back I had to washer up my left hanger bracket but I doubt you’ll have this problem on a GV. Just out of interest what tyres are on it? If it’s the Shinkos (I doubt it being that old) please get rid! Might be worth looking for a front fender extender too if they do one for yours :).
Oh okay, yeah an ecu flash seems super risky indeed, I was only thinking about it cause a friend of mine recently flashed their Honda Monkey 125 with pretty cool results (noticably faster accelleration and higher top speed). But I think with the chain, clutch, and possibly spark plug upgrades I’ll be fine until I graduate to a larger displacement.
I bought my gv125s secondhand but I’m pretty sure it’s still the stock tyres on there. I’ll take a picture tomorrow and post it here so people can check.