Sorry if this turns into another oil debate thread..

Used Mobil 1 15w-30 this last oil change and my clutch is slipping like crazy! Not so much in lower gears but when i'm in 3rd i pin it and watch the rpm's redline and i dont go any faster.

Gonna do an oil change 2nite. With a non-synthetic oil.

This happen to anyone else?

 

I'm a ****ty mechanic, but I know that Honda recommends 10W-40 weight oil. After that, I've never heard of synthetic / non-synthetic making a difference (or at least as much as you're experiencing).

I personally use Spectro Golden4 semi-synthetic, if it helps at all.

 

A lot of guys here use synthetics without problems (including me). Perhaps you accidentally put an energy conserving oil in there. I couldn't find a 15W-30, but there is a 5W-30 energy conserving which probably has friction modifiers causing the slippage. A highly used synthetic is Shell Rotella-T 5W-40.
Here's a good moto oil forum:

 

synthetic vs non-synthetic isn't the problem, nor is oil viscosity. you most likely used energy conserving (Molybdenum added) oil. using it isn't really a problem for short periods, but you don't want to use it over the long haul...

 

i heard wet clutches and synthetic don't mix, maybe not. My clutch has been taking a lot of abuse lately from wheelies (not to sound like a squid ), might need new plates.

 

Honda conventional all the way!