At the left a picture from a He-Ja Piston from the Yamaha YZ125 from 2005, which we have prepared, and by now has run more than 10 hours.
Look very careful at the beautiful size of the combustion on the piston. We have mounted a 490 main jet in the carburettor and a 40 pilot jet, whereupon we achieve this well looking result as the picture shows.
This is also possible because by now the factory has mounted the carburettor now right behind the barrel, giving us the possible to achieve this result.
It was always a problem to get the streaming centric, which as you can see is perfectly succeeded.