Maybe I didn't make myself clear. When you start from a stop, do you pull the throttle wide open, or pull it like 1/4 open?
If it bogs when you pull it 1/4, your main jet isn't the problem, it's not even active yet (look at the throttle chart in the phbg wiki).
It would make sense for WOT to bog if you're starting from a stop.
Do you have the choke hooked up? That can be very useful to tell if you're lean or rich. Bogging that much from a stop _could_ be lean OR rich, I've experienced both. That's where a choke comes in handy, pull the choke and start it, if it bogs less, you're running lean. If it totally dies, or bogs more, you're rich.
The choke was my favorite tool for tuning my 103, because doing plug chops is next to impossible on a phbg. Where in SF can you ride in only one throttle position for a quarter mile and how many plugs are you willing to waste. I had to do it based on feeling, I'd jet everything and use the choke to find exactly which jetting in each throttle position was just below 4-stroking (safe zone).