Suzuki 2 Strokes

HI
could anyone please tell me if there is a simple way of doing this without taking the clutch assembly and alternator apart/off? In other words, is there a relatively simple way of taking the engine unit out and replacing the seal on, what i assume is number 3 piston end of the crank?
If anyone has a step-by-step guide, i would be grateful. My maintenance skills are not bad (have rebuilt engines in the past) but i am also the king of unfinished projects and i dont want to start it, then leave it cos there was something complicated which i hadn't figured on encountering. I have the original suzuki gt380 manual but it's a big vague in places.
any advice appreciated

M in Beirut

The general way to replace the crank end seals is to split the cases , i have hears of guys getting the seal out and putting a new one in without splitting the cases but thats not the best way as that area has to be air tight .. any air leaks could cause a seizure on that piston .