you need to remove the 2 large nuts and remove drum like people are saying. its real simple and something you can do yourself. check your linkage like big g said. when you move pedal make sure the parts back by the brake drum are moving. this could be as simple adjusting the brakes but there could be other problems. the brake actuator is what normally causes the brakes to stick. it the part that the linkages connect to and goes through the brake housing and moves the brake shoes. it gets dry and rusts up causing it to stick. take the arm off it (on the outside) and the brake shoes and it will slide out from brake shoe side. wire wheel it and put some grease on it and reassemble it. then if your shoes look good still you can adjust things to get it working properly.
Trikes: All Honda: 84 250r, 85 86 and 87 250sx, 84 and 85 125m, 79 82 84 and 85 110's, 73 us 90 and 77 atc90, 75 atc70
Cycles: Honda: 71 cb100, 78 cb750 coming soon cb750 trike. Yamaha: 67 yds 3 (250cc, 2cyl, 2 stroke), 82 750 SECA
Other toys: Chenoweth VW sandrail dune buggy, old race go kart, racing mower, 76 Arctic Cat Pantera 440 snowmobile
KEEP IT ON ALL 3 OR AT LEAST 2 AT A TIME