thanks fontyyy

well my current motor has the 2t oil in gearbox problem, had to ride it yesterday as it was my only mode of transport, i did remove some of the contaminated oil and topped up with some gearoil on the way to work and did it again on the way back.

i've been told that i would get 2t oil in my crankcase, was just wondering what sort of problems could i have caused?

i also found these links from the site
http://www.nsr250.net/forums/viewtopic.php?p=7342
http://nsr250.net/forums/viewtopic.php?p=40663&highlight=stroke+oil%2A+gearbox#40663

on how to reseat the o-ring which i will try first, but i also have a mc28 motor which has been sitting for over 2 years which was taken from a crashed bike, what would i need to look over before fitting, from memory... i think it was rebuilt maybe a few thousands k's before the accident