Are 250s essentially the minor leagues?

450 are v slightly faster motorbikes (compare the fastest lap times 250 v 450), but I think there are physical limits to how fast a motorbike can be ridden on a track - like the maximum mph in a corner, the rest is technique/ tactics on jumps/ obstacles and is in acceleration on straightaways (higher bhp in 450). With a bigger engine 450 has more torque and go a bit faster, quicker, for longer, though they’re a bit heavier too 

If we’re talking racing, it’s all about times and who is fastest. Of course the analogy isn’t quite complete because if you were an Olympic sprinter you don’t have the option of a choice like ‘shall I wear my superfast 90bhp shoes or just my regular fast 70bhp shoes?’ (For example)

Which is unlike boxing, where you have a ‘fair fight’ for example with weight classes 

So then i guess you get paid more on a 450 because you’re quicker, you’re the fastest rider on a 250 or 450 motorbike (but it’s sort of not a like for like comparison), no one pays anyone because they’re slow lol

To carry on the racing theme, it’s ridiculous that people don’t understand why lappers are on the track, it’s a race - an athlete wouldn’t quit halfway through a race, not to mention anything can happen, too 

Do the winners get paid the same in both classes? 

Thats the only fact we need.