[Kennedy541]

POWROLL PRODUCTS FOR THE YAMAHA TTR110
You have to bore the stock cylinder for these.
Otherwise you can bore the stock cylinder to fit a 1st over wiseco klx high compression piston such as this member did:
http://planetminis.com/forums/klx110-drz110-ttr90/126315-ttr124-big-bore-kit-ttr110.html