evolution of suspention

Crash Course in Suspension Evolution 101: Your 1990 YZ the product of all the testing/learning that was done threw the 80's. The rear shock is much like one on a newer bike just really in the fact that over the years the main real differences every year the shafts get alittle bigger and hold alittle more oil. The biggest changes to rear shocks in the 90's was the ability to udjust the high speed compresion yourself but this is not a new concept. Front Forks pretty much peaked with the cartridge system came out and were about the same for the most part. With the biggest changes being in tube diameter and changes to the way the cartridge flowed the oil. The mid valve hit in the mid 90's but nobody could tell if it did anything at first (I find this kind of funny) The biggest change was when showa came out with the twin chamber forks (yamaha owns the rights) Kayaba. had the mid valve with the rubber bumper forks came out in 95. and in '00 kayaba's bladder forks came out. I could exsplain this much better in person but after about hours of my constant rambling of exsplaining a damper rod fork vs a cartridge fork vs convention fork vs inverted fork etc you'd be even more confused hehe. but you kinda get the idea or are you more confused now? :)

I'd say get the newest machine you can afford, suspensions have improved alot over the last 20 years. The old bike jumped worse than your 125 because it is an old design, not because it was a 250.

Oh yea then we can throw in the whole aspect of chassis design changes, IE. swing arm/linkage, linkage ratio's, Steering geomerty , spring rates etc puts a whole new spin on things. The varibles/combo's are endless.