one of 3 things check in order
1,it has too much oil in the engine. there is an allen bolt in the middle of the clutch cover undo that and hold the bike upright and make sure it not running out of the hole if it does then let it run out until it stops and then refit the allen bolt.
2,you have the wrong grade of oil in it and it has too much detergent in it which is frothing and causing the oil to double in volumn with air bubbles.use straight 10/w40 mineral based oil.
3,the clutch pivot shaft seal is damaged and is letting the oil leak past it.
adam bike doctor, June 2010
