Open pipe

[SuperEX]

I am running an E-series slip-on 12 disc's and a spark arrester, Is it ok to run with out the spark arrester? If I take that out, It's like running a straight pipe, Is this hard on the engine?

[Steve-o 400EX]

No, running with no disks and no spark arrestor will not hurt the motor at all. My best friend runs like this with his E-series. Just make sure you run with the tip on there to give a little back pressure. It will also give you a nice power gain without the disks on there.:macho

[Dave400ex]

Nope it will be fine. Just make sure you Re-Jet because a lot more air will be flowing out faster. Mine is wide open....