After changing my oil today I was checking for and leakage and noticed both my headers right were they come off the engine were glowing a pretty decent shade of orange. After a ride I noticed the rear cylinder's pipe was glowing almost red while the front looked normal. So i'm just wondering if this is normal? Sorry if this is a dumb question but none of my inlines ever did this and I just want to make sure I'm not running lean. TIA for any help.