Servicing my 92 rm250?

Well first of all i would replace all of your fluids. Next you are probably going to want to do a compression test to see if the top end is gone or not.

Ill add in more later i g2g to school :)

How does it run?

Have you had the bike out? How does it run? Is it strong? Any fluid leaks anywhere? Any clutch slippage? Any balck spooge coming from the exhaust?

Give us a little insight.

The 92 RM250 was a good bike. The forks are grim stock. Thec stock jetting was rich, but I don't remember what I used back then.Tranny oil is 650cc. I used to use 24 oz. Any of the motorcycle oils work well in the trans. BelRay Gearsaver,
Maxima MTL and Hondaline ProTrans oil are tranny specific oils that work good.
A bike that old you should go entirely through it maintenance wise. Buy a Suzuki manual or a Clymer.
That bike has the ugliest OEM seat cover of any motorcycle ever produced. It was Prince Purple Rain purple and puke yellow leopard print. If the cheezy stock cover hasn't fallen off yet, just rip it off and ride on the foam at least it will look cooler.
That bike kind of felt like a big 125 with not a lot of lowend power, but it came on hard in the midrange. A ffw. woul smooth it out.

You can do everything yourself. Buy a factory service manual.

Things that I would check and/or replace:
Piston & rings, reeds, carb jetting & float height, timing, bearings, leaky seals, oil, brake fluid, fuel, air filter, silencer packing....