lighter oil = more power

i changed oil today, from amsoil 20w50 to amsoil 10w40. (its winter here in the southwest USA). i did a few miles warm up ride, dained the old oil, and put in the fresh. i have to admit , there was a significant difference in how easily the engine rev's, and it feels like the bike accelerates faster. the transmission seems to clunk a little louder between gears though.
please tell me i won't harm anything by changing the oil viscosity. . . :?

As the mech of the shop I bought mine from said, "It's a truck, it can take quite a lot." from back when I thought I was having oil troubles and ended up mixing semi-synthetic with regular. Doh!

ATM

Look up for the sticky on oil. You are absolutely in line with my discovery, backed up by techs from amsoil and others. Enjoy the new power, better mileage, etc...

A good friend of mine, who is a car nut, did some research on the synthetic oils, especially our favorite, Mobil 1.

Seems that only the original Mobil 1 synthetic is truelly fully synthetic (in the Mobil lineup.) The extended performance is a semi. Has something to do with another oil company declaring a semi of theirs was "Synthetic" and getting away with it, so Mobile said, "we can do that too."

Anyway, after seeing several company vehicles go through grueling abuse and neglect with only Mobil 1 for protection, and my own personal vehicles make it way, way over their life expectancy, I only use the Mobil 1 full synthetic oil.

But that's just my opinion.

ATM

Mobil Full synthetic MOTORCYCLE oil (MX4T?) or Amsoil full moto syn (Amsoil squeaks by the Mobil motocycle oil-but both are so high up the syn chain I'd stick with Triumph sanctioned Mobil till OOW).