Jumo 628 said:
One of my riding partners had an 02 and he's a very fast Vet A racer in our district. It might have been a 520 then... no major changes i spose.
Major changes.
The 520 SX & E/MXC motors were the same, but the 525 SX has a different bore & stroke (more oversquare like a YZF), larger carb, and bigger cam than either the 520 or 525 E/MXC motor. Totally different animal IMO than a 525 E/MXC motor (which is relatively unchanged from the 520 E/MXC motor).
The frame geometry is also markedly different between a 520 SX and 525 SX, as are the forks.
I haven't ridden one on a track, but they are a major handful in the power dept. Like a YZ 450 on (a small dose of) steriods.
Unlike the 520 SX, the 525 actually turns. It reminds me more of a KX in this regard than a KTM. I think they "only" changed the offset, but it feels like the rake is different also.
But the happy/smooth/friendly/warm&fuzzy E/MXC powerband is not there on the 525 SX. I really think it has more in common w/ a YZ 450 in this regard.
Just my opinion, I've not owned an orange bike but have ridden several 520s and 525s.
Hope this helps.