Exhaust Question

[ginobili07]

OK I have a 02 400ex with a HMF slip on and want to get a upgraded header, i am more of a trail rider and don't plan on doing much more upgrades on it. I was going to get a FMF powerbomb but am thinking about getting a FMF Hi-Flo instead since it is cheaper and i really don't need the Powerbomb since im not going to be racing or doing any extreme riding. Does anyone have the Hi-Flo? Just want some thoughts, THANKS

[ginobili07]

Any thoughts?

[bbender85]

if you're not going to build the motor, don't even bother with an aftermarket head pipe.

[yellow416ex]

I have to agree, if youre not going to build your motor and your not racing then your best bang for the buck would be to grind out the welds on your stock head pipe

[ginobili07]

What exaclty do you mean by "grinding out the welds on the stock header"?

[yellow416ex]

Originally posted by ginobili07
What exaclty do you mean by "grinding out the welds on the stock header"?

when you pull your stock header off you will notice the welds inside the pipe are about an 1/8" thick maybe thicker. what you can do is use a dremel and grind them down to the diameter of pipe to make it less restrictive.

if you do a search on this someone has made a thread with some nice pics to explain it better

[dariusld]

Originally posted by hornetgod13
Here's a picture of one stock welded header pipe and the other after I opened it up another 1/8th of an inch.

[ginobili07]

WOW that picture really lets you see the difference i think i am going to just do that instead of getting a aftermarket header. And grinding down the header welds doesn't hurt the header or cause any issues?

[yellow416ex]

Originally posted by ginobili07
WOW that picture really lets you see the difference i think i am going to just do that instead of getting a aftermarket header. And grinding down the header welds doesn't hurt the header or cause any issues?

you should be just fine. its still plenty thick where it needs to be

[deathcorefan2]

lol thats cool, im going to do that when i take my headers off to clean them up. thanks.

[ae13291]

i also grinded my welds off, was very easy too, im sure it made some kind of performance after seeing how much the hole was opened up

[rideracelivemx7]

you cant use any ol bit on the dremel, you need a carbide bit, the welds in that beast are very very strong, took 45mins for me to get halfway threw mine, and 5 bits later i gave up, the enarest shop didnt have the carbide bits and the welds will chew threw your stock dremel bits.

[ginobili07]

Alright thanks alot everyone, when spring comes around i will give that a try and let you know how it worked out :)

[Snipe]

If I did any upgrade at all I would change it from steel to stainless. Stainless will let heat exchange faster giving the bike a deeper tone and more power gains.

[ginobili07]

Well the Hi-flo header is stainless, but if i stick with stock i cant exaclty change the type of metal it is.