The bike is really fun, but yeah, it just feels dangerous to me with that all-or-nothing power, and its so different from my other Tiara which is a better all-rounder. maybe 1500 if it meant getting an all new carb or something like that. I should have clarified I don't want to spend more than a thousand baht or so on the fix.
If your having wheelie problems (is that really a problem ?) this may not be the best solution and may want to go up one tooth instead of down. If you want a quick fix go down one front tooth, the bottom end will be stronger and blend better into midrange.
The judder springs are also commonly removed for a better bite off the line, if the bike wobbles and lurches on take off, they've been taken out. The pulser sensor may have also been filed to advance the ignition, this is a cheap fix at around 150 baht installed, its located by the magnetic flywheel. Alternatively the spacer can also be placed at the bottom of the cylinder instead. The spacer needs to be there so the piston doesnt smack the head. I use to run offset crankpins 10 years ago when i raced, if you look at the head gasket, if there is an aluminium spacer about 2-3mm thick, more than likely theres an offset crankpin installed. Where after it winds up it'll take off like a scorched cat. Bigger the carb more mid-top end you'll have and less bottom end, especially in the case of a two stroke.
The original should be 24-26mm, these bikes usually get 28mm carbs installed and sometimes bored out to 30mm. Like Karlos said, its probably a bigger than standard carb.