I recently changed oil my type from Yamalube to Mobile 1 synthetic. I noticed my clutch started slipping on heavy acceleration. I haven't noticed this before the switch. I usually ride sand, but the other day I rode on some hard pack and this is when I noticed the slipping. I guess it could have been slipping the whole time and I just couldn't notice it in the sand. I believe that Mobile 1 is OK to run in this bike as it has no friction modifiers. So is it the oil or the clutch? Also, I am starting to think about a new ride. My 03 450 is starting to show its age and I'm not sure if I should invest money into it or get a new machine. As it is now my clutch is most likely going, I need a suspension work, new rear tire and my plastics look like crap. Otherwise the bike is great, I had the engine rebuilt 6 months ago and just replaced the chain and sprockets. My issue is this; I have about $1500 saved in my bike fund. I figure I can do all the needed work on the bike to get her up to speed or, I can use the bike as a trade in with the 1500 for a down payment on an 06. The thing is, I would be able to fix the clutch, trick out the suspension in my 03 (stiffer than stock springs), have new plastics and a rear tire with that money, or deal with the stock suspension and set up of the 06, and of course have to make payments. I hate payments. Would I be much happier with the 06 or my tried, tested 03 with a suspension upgrade. Any advice?