Noisy motor bike in Boveney Road

Every day several times a day, but mainly in the evenings. Is it legal to have a motor bike this loud, has something been taken off it to purposely make it this loud?

Maybe and yes.

If you can quietly find out where they live and ring the non emergency police number they can have a chat with them (about an illegal exhaust). From Google it seems you don’t have much recourse and neither do the police because they get an MOT with a legal exhaust then swap in an illegal one.

The police can issue them with ( from memory) a section 59 order if the exhaust is causing issues. Of they breach the order the bike is confiscated. You however have to provide them the bike number and make a complaint. Talk to the local SNT team