Hi Guys, i really need advice on oil leaking problem. On the left side of the bike, near my front sprocket there is a constant oil leak. How do I change oil seals?

Sounds like your output drive shaft seal to me, crankcase splitter if I'm correct, big job.

I think it is. I looked at doing this because I'm sure I've got something a little weepy in that area, and it would appear that the seal sits in a recess, and is sandwiched between the upper and lower engine cases. You might possibly the oil is coming from elsewhere, so it may be beneficial to take the front sprocket off, clean everything up and then run the engine to see if it's definitely coming out there. However, it may take a long time to build up until you notice it is there, and it might also be the case that unless the engine under load, the leak is minimal anyway.

If it really is leaking, I don't envy you!

Only other seal in that vicinity (apart from the output seal) is the clutch push rod seal, which doesn't require the cases splitting and is much cheaper/easier to replace. I'd be absolutely sure that it is the output seal before as it is a pretty big job!