You would be fine with full synthetic.. but they dont make full synthetic in 10w-40.... They make a Great dino oil 15w-40.. I can show you what the inside of a TLS motor looks like with 60,000 miles on it, and 500+ drag races if you like?
I always thought you shouldnt run full synthetic for ages (Define ages: I have no idea). I think mines on 50/50 and it's done nearly 19000km (12000 miles). I'm hoping going full synthetic will help with the Kawi gear changing clunk :/
there's all sorts of theories on oil, tires, and breaking in a bike.
i subscribe to the changing the oil all the time (3-4 times) before 500 miles. All using dino oil. Then again at 1000, 2000, and 3000...still dino. 6,000 goto a semi-synthetic, 9,000 full synthetic. I've got 10x-40 Redline oil in her now. :O
you don't want to know about the break in method :laugh
i believe you are supposed to use reg oil. synthetic is very thin and dosent offer the protection that the wet clutch and tranny need to keep from tearing its self apart. reg oil or dino oil breaks down faster but offers more protection. also the motorcycle oils like kawi chem and maxima and others have different detergent levels than the ones you can get from wall mart. i use maxium4 premium 10w40. its cheap and its the right kind for our kind of motor/trannys. i have done alot of research on this subject, not just poking around forums but actually contacting manufacturers and distributers to answer my questions. these are not car engines they spin at 16,000rpm and require specially formulated oils. yes a synthetic will protect your engine and you will not see any imeadiate problames, but if you use the right stuff regularly(every 1,000mi)it can easily double the life of your engine.