not the same exhaust question

[Jgrimm400ex]

If i gut my stick pipe do i need to change jetting.
or If i just drill a couple of holes change jetting.

[TRX_Thumper]

just depends nobody can answer that only your motor knows....but more than likely no ...i would do the gabe mod to the stock muffler...then yes you will have to rejet...maybe someone here knows the link to gabes website i dont remember it

[Jgrimm400ex]

What is the gabe mod. do? Where can i find them, anyone.

[cals400ex]

i believe this is the mod where you take your spark arrestor out and drill a few holes in the plate behind where the spark arrestor normally is. when you look i there you will see one hole. drill a few more. usually peole drill two or three 3/4 or one inch holes in there. i did not have a bit that big so i just drilled several smaller holes in there. i am running 152 mainjet but i also have a modded lid. will you notice a gain? i really don't know if i did or not but i did it and it does not run worse for sure. i usually am a little faster than my friends and he has a big gun slip on, k and n, and jetting. i change the jets around so much though to get the best performance. i noticed adjusting my valves made more of a difference than gutting my pipe, airbox mods, and jetting did combined.