The Yamaha YZF-R1 Fueling Mystery Still Unsolved

It's been an odd month really, I'm over the moon with the way the Yamaha YZF-R1's fueling and transferring its power to the rear tire. It feels crisper, sharper, more responsive, more mental than it has done in months, and yet it seems, for want of any explanation, to have lost 7 horsepower.

When I took it up with my mechanic, the first weekend after I received the YZF-R1, my mechanic got it all set up and mapped, and kicking out very decent 168 horsepower. However, as time passed, the Yamaha YZF-R1 began to smell like it was running rich. When I checked the R1 on an dyno a month or so ago it was making 158 horsepower, and confirmed the fueling was out. I can't begin to explain how weird that is. Getting the Yamaha YZF-R1 back to my mechanic, and his dyno said exactly the same thing. A lot of head-scratching followed.

My mechanic was beside himself trying to figure it out, but in the end there was nothing for it other than to map the Dynojet Power Commander III again. All dialed in, wit was perfect, but not making 161 horsepower. Of course, I may simply have dropped 7 horses somewhere, I'm careless like that sometimes. If you see them, please contact me...

It's the same dyno, the same bike, the same mapping guru, all the same engine and drive components, and even the weather wasn't wildly different, yet the graph look like two completely different motorcycles. As mysteries go, this one's a serious brain twister...