Is it ok too run a mega max2 without discs and is this doing any damage to my engine or not ?
And do I lose any power ?


2001 400ex
nerfbars
dg bumper
fmf mega max2
renthal handlebars
motion pro twist throttle

 

The system is designed to work with the disks, it's designed for the back pressure created with the disks. I would suspect that running without the disks would lose power on bottom and midrange, with maybe a tiny increase at peak rpm.

If you want a more open system, try one of the mufflers that's designed as a racing system with a reverse cone megaphone. They'll give you more power throughout the range than what you're using now.