Novarossi engines last so much if taken well care of, that my opinion is to get a new engine instead of replacing the linear/piston... By the time the engine asks to have a linear/piston changed, you will find that the bearings will probably also need a change and that the crankshaft and crankcase/head/carburator might be the only thing that you dont need to replace. The only thing I change in all my engines after 1 gallon of fuel is the conrod, and piston rod. Why? Because no matter what engine it is, 99.9% of them break in the conrod, and by making sure you have a fresh conrod, it will not break through there. I have seen novarossi conrods last over 3 gallons of fuel and still running strong, but I never take changes with a $500 engine.

But to answer your question... piston/linear/conrod is about $200-$250... $100-$150 more and you should be able to buy a NIB engine...

Novarossi conrods should be at $30-35...