What is the advantage of having a short straight part in the head pipe as it comes out of the motor vs one that just curves? Here is an example. The first picture is a PC head pipe for a 03-05 yz 450. The head pipe curves the whole way around and then goes back. The second pictures is another PC head pipe that is also for the 03-05 yz 450. Here you can see the bend is different my Dr,D pipe off my old 450 looked like this. My DRD pipe made great power over the stock yz one. Anyways I just wondered as I'm pipe shopping for my new 06 wr450. Thanks.