The brake light staying on is not normal. I would suspect the ignition switch. Follow the wires from the ignition switch till you get to a connector (you might need to remove some plastic bits to gain access). Unplug the switch. If the brake light goes off then your ignition switch is bad.
I have a couple of generic 110cc quad manuals. They aren't for your specific quad but 110cc chinese quads are oftern so similar the manuals are interchangable. These aren't full blown engine service manuals, but they cover routine maintenance items such as valve adjustment, clutch adjustment, etc. Send me your email address by private message if you want them. You'll need to be able to receive about 5 megabytes of attachments total.