Head work

[moto4racing]

Who make your head jobs ? A normal machinist ?
What is the trick (the best valves, best size, best modification) to have the best air flow? A header is it needed after the job?

 

[rbod]

I ported my own head and cut the intake out for a 41mm valve. The exhaust is quite pinched and restricted. The intake just needs a little massaging. I'm sure most motorsports places would do the work.