The BR7ES is one size hotter without the resistor, but as Glenn said, that is not the correct way to fix the problem and it could cause bigger problems. If your plug is loading up so that you have to pull in the clutch and rev the motor to clean the plug off so the motor runs clean, try going 1 clip leaner on your needle and work from there until you get it right.
Or better yet, if you are unsure and have a riding buddy who is good at jetting, let him ride it for a minute and he will be able to tell you what to do and probably do it for you.
Also, in the middle of a typical section where you are running your bike at its hardest, stop it immediately, pull over and check the spark plug. If it's dark brown and wet from unburned fuel, you're definitely too rich. If it's white and dry, you're on the lean side.