yahh it's true.. but lots of change on the cyl head.. no more liquid cooling on the cyl block... but cyl head still using liquid cooling...
ok.. pardon my bad english.. in short the 300 cc cyl volume came from :
1. bore x stroke : 71 mm x 76 mm (stroke increased from 58,7) using Yamaha Scorpio piston with special made piston boss pin (scorpio's piston pin diameter is 16 mm while stock T135 is 14 mm)
2. Liner taken from a diesel engine, engine block liner hole was enlarged up to 76 mm
3. Increase in stroke was made possible by moving the crank pin and welded by electric torch.
4. Connecting rod was taken from Honda CB100 K5 because the big end diameter is the same as stock T135 crankshaft.
5. The rest is to make a lower cyl adaptor from aluminium with 15 mm thickness to compensate the stroke increase, and 0,5 mm head gasket.
6. Engine valve was taken from Raider 150 with 22 mm inlet valve and 19 mm exhaust valve.
7. Carb using Mikuni TM32, with 45/150 pilot and main jet size.
No detail about the timing chain.
I think someone here already said that this kind of upgrade was impossible, well, i think this proves it.
Those who dare to try this may contact Oliver at +62811188132, they said they made a commercial kit for these setup.