[Racer X]

I was racing at Maxton in June. It was 115 deg f. I made 6 passes on Saturday All at 101 . something. On Sunday it started all over again . Like a bracket drag racer .I was stuck at 101 mph then at lunch I figured with 115 deg and 80 % humidity . I needed to lean out my mixture. I was running 104 mph just a month before with the same set up.
I have a full Yoshie set up with K&N filter pods.
I figured if I pulled the muffler it would loose some torque but may lean things out.
First pass with out muffler went 103 then 105 then my fastest speed ever at 106.760mph .
So I would say you may get 5 mph top end loose some torque and yes it is loud as hell @ 13000 rpm.
Another cool thing is fire comes out of the short pipe

 

[Racer X]

The guy running the timing tower at the Maxton race track called me the angry Bee.
Now he has bin watching big block Chevy's and all manner of vehicles going buy at full throttle for years. My 250 was so loud he made comment about it. That should say something about how loud it is a 13000 rpm with an open pipe.

 

[Racer X]

If you pull the muffler off the stock head pipe the cat offers a some back pressure. But Ya you will loose some bottom end. This weekend I will try to post a vid of my bike with the open Yoshi. Maybe if I record the sound from across the yard or down the street it will give an impression of the noise.