I just switch to 10w40 Mobil1 full synthetic on my 08 ninja at 3000 miles. The bike seems to shift smoother than before but thats probably just me
On my 97 ninja 250 I ran regular cheap car oil and didn't notice any slippage. Just make sure you don't get the energy conserving stuff. I also used the shell rotella oil that many are using and didn't notice a difference.
If there's ONE question sure to generate a SH!T storm in any motorcycle or car/truck forum, you just asked it!
This should be required reading before any further discussion. Read the information at those three links, then decide. There IS a VERY definate chemical difference between the additives in car/truck oil and dedicated motorcycle oil, and your oil is wearing out much faster than you think that it is!
That said, I switched my bike to Shell Rotella at 1700 miles and never looked back. The most imediate thing that I noticed was much more positive shifting.
__________________ Kawi Green '09 Ninja ZX6R. Fender eliminator, frame plugs, OEM seat cowl, Shogun frame sliders & mini spools, Rascal Grafik zombie tank pad, Zero Gravity double bubble dark smoke, Pazzos long and short, Attack engine covers, 724 green grips, SpeedoDRD, Galfer black brake lines. Zodiac Mindwarp and the Love Reaction If I have to explain, you don't get it!