I got a 03 rm 250 and it smokes to wear there is oil resadue on my rear fender

sounds like worn piston rings. In 1st ans 2nd gears the engine wants to rev highest to make maximum powere so rings get a bit worn and oil will be sucked past. Change the rings and try again

If it was white smoke coming out you may have blown a head gasket. If it is water cooled and there are no signs of external leakage then it only has one other way to go, inside.
If you have an oil dipstick, pull it out and check to see if your oil looks more like a milk shake sludge. Even if you can't see it, try dumping your oil from the sump and take out your oil filter. (unless it is a 2 stroke)

I'm pretty sure you want to use gear oil in the crankcase of a two-stroke,(like 80wt Bel Ray).
Standard "car weight" motor oils are 4 stroke, designed to lube the crank & cylinders. your '03 RM has the cylinders lubed by the pre-mix...
A motorcycle specific crankcase lube is the best bet; lots of differing opinions on the wet-clutch aspect.

I would suggest doing a compression check and checking the results against your manual (should be at least 165PSI or so. Low compression will make the bike run rich which would make it smoke excessively. It would also make it hard to start and run poorly with low power. New rings could do wonders.

Scott

Is this bike a two stroke or four stroke.Meaning do you mix oil n gas,or dose it run on straight gas .If this a two stroke,its normal to blow blue smoke,but not that bad.Sounds like the person before you put to much oil in gas or piston rings are shot.There are exact oil to gas ratios you must follow with a two stroke engine.If you dont, you can have all kinds of problems.

The '03 and '04 K1, K2, and K3 models use the SKU# 59480-36E30. The '03 and '04 K4, K5, and K6 models use the SKU# 59480-37F00. Personally, I would take the old hose to a dealer and match it up to a new one. The difference in SKU numbers could be simply the supplier or the finish on the metal fittings. If you want to see what K number your bike is, go to the following site and input the VIN number. NOT THE ENGINE NUMBER.
Please rate my answer. Thanks.
http://www.motoverse.com/tools/vin/kawasaki.asp

You should be running a good oil at 32:1. If you are, and still get oil out of the pipe, your jetting is too rich.

Probably due to a bad crank seal on the clutch side. The extra smoke is from the trans fluid burning through the cylinder.

id say its time for a new set of piston rings sounds like youv got a busted oil ring

could be too much 2 stroke oil in your mix or worse case, your piston rings are going.