Well everyone I come with an interesting story.
A while ago my engine was making a weird clanking / rattle noise upon deceleration, in fact I opened a thread on the issue:
http://www.venturerider.org/forum/showthread.php?t=61278&highlight=engine+rattle
Anyways, under the suggestion of my local Yamaha dealer, i did a complete oil change and switched to the Yamalube 10w 40 mineral oil, when I originally used a synthetic blend Castrol Activo 10w 40. Mind you the bike at the time had around 6k miles.
Within 200 miles (4 days) i noticed clutch slipping through the high gears, especially 5th when i was trying to pass. I tore the clutch apart to see if the spring or any of the friction disks and clutch plates were within spec (yes they where). Put it all back together and same issue. So i grabbed 2 cans of brake cleaner and tore the clutch apart. Removed all the clutch components and thoroughly cleaned all of them. Replaced the oil with the original synthetic blend and the problem has gone away. I do realize that to conduct a proper experiment I should have put the mineral oi back into it to see if it did it again, but I just did not want to go through and dismantle the clutch again.
To me this sounds weird, but I'm sure there is a logical explanation.
Thanks for your continued support. This site is awesome!!