The Blaster is a 2-stroke. Different critter altogether..
Kits for the TW probably wouldn't sell very well because the case mouths won't accept much of an overbore. Oversized pistons exist and any reputable shop can bore your cylinder, it just won't yield much bang for the buck. Standard bore is only 67mm yielding 196cc. A 1mm overbore only yields 202cc and a 2mm overbore is 208. Lots of munny and effort for a 10% gain.
Opening the case mouths takes things out of the realm of the simple "bolt-on" big bore as it requires splitting and machining cases, but it allows you to move up to the 225 cylinders which have a 70mm standard bore.
A 70mm bore with the TW's 55.7mm stroke yields 214cc. 227cc if the 225 cylinder is overbored to 72mm.
Add the 225's longer stroke 58mm crank and you get 223cc with the 70mm bore and 236cc with a 72mm overbore.
Those are about the max displacements using pistons which are readily available.