Quote:
Originally Posted by Water Warrior 2
How much increase in cc's will you get with a bore n stroke job?
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Several of my friend do boreup with
76mm piston (originally piston of daihatsu zebra)...about 275cc
78mm piston (originally piston of KIA sephia) about...300cc
Both of piston above has same stroke pin diameter with GZ so its make modding job easier
1.buy one of piston above
2.bring cylinder block to garage that have honing machine etc....
3.buy new diesel boring and process till its have same inner diameter with our new big piston
4.reshape edge of dome head with foredom rotary tool till its match with new diameter piston (its kind of dentist drill tool)
PS : not all of gs250 here has do boreup...mostly still using original piston including me...
But replace stock piston with larger diameter still a common mod even for a 125cc cub