YamahaR15

I have a few answers to a few things. ECU hacking you cant do it . max you can have a piggi back system to give more fuel and air to the bike but there is nothing available for the YBR 125 About the noise . Your tappets might have gone loose . hence the bike is become noisy. Hack EFI ?? what do you want to do with it . i am guessing the YBR 125 has a open loop fuel injection system. Regarding the diagnostic tool .its a useful tool where you can change the Air fuel mixture and basically have some control over your tuning . If you want to do some serious mods would suggest check if there any big bore kits for the YBR 125 and upgrade it to a 150cc or a 165 cc bore kit and just change the Air fuel mixture and fly . PM me if you want to know more regarding the yamaha Diagnostic tool. I have a friend who sells it here. I own a yamaha YZF R15 here in india.