300factorybeta4t

For your weight you should run 300cc of 5wt suspension fluid in each leg. Make sure the spring preload is wound right off and then have a play with the rebound damping to suit.

have you checked the position of the switch?

If it's overflowing with new/different carb on it then it has to be something already on your bike. make sure the fuel valve swithch is in the up position, if it's down the fuel runs continuously into the carb.

Before going to the expense of master cylinders etc try removing and checking the pedal pivot bolt. As it gets worn it gets a high spot which causes the brake pedal to momentarily lock down. It's probably happened more than you've realised! When the bolt and pivot bush is out give them a good clean and put the bolt back with some loctite and some light grease on the pivot, don't overtighten it. Once you get in the habit of doing this as part of your service routine you won't have the problem again.

Check the fuel solenoid/valve, it sounds like it could be in the open position or possibly faulty.