Don't know what Yamaha recommends but I run mine at .028/.030 with the SS kit.

Tried up to .040 but she don't like it when she's cold.

 

The wider the gap the more energy it takes to fire the plug especially under load. .030 sounds good to me.

 

I just replaced my plugs after 11k ( they were FINE, I have checked them before) set them to .035
last time I looked at them ( 8k ish ) they were beige... yesterday they were black... I'm guessing it has to do with my K&N's getting dirty...
Would love some feedback on that....

 

If your filters were bad seems like it would be down on power.