give it a good soak in penetrating lubricant and try a three-jaw puller, or a bearing puller, its probably rusted and party frozen on in there. some heat will help too.
i like how they put the pedals higher on the newer subframes..and plastic fan, and the weird belt guide thingy i've never seen before. keep the pics coming.
actually, can you take a pic of the other side of the sub-frame showing the area around the carb. my original one had holes all over there and cracked, got a later replacement that was a better stamping with fewer holes, wondering about the 2000s models.