Modified Head Pipes

[Z400/400ex]

I keep hearing about people modifing their stock head pipes, whats the deal with that??
Do they just grind down the weld inside the pipe??? :cool:

[stupid driver]

ya, thats what you do. There are 2 welds on the inside of each headpipe. Grind them down w/ a dremel tool

[Z400/400ex]

TWO??? I see one? Also do you grind them down flush??? :confused:

[Pappy]

maybe its just me buy i havent seen a headpipe with welds so large that once ground down would be any kind of an improvement:ermm:

[UglyMotha™]

Originally posted by Pappy
maybe its just me buy i havent seen a headpipe with welds so large that once ground down would be any kind of an improvement:ermm:



word :ermm:

[pnut420]

Originally posted by Pappy
maybe its just me buy i havent seen a headpipe with welds so large that once ground down would be any kind of an improvement:ermm:

My stock headpipe had a huge weld that could have been ground down alot, but Im getting the X-6 instead

[tprender]

I have been told by the people at GT Thunder from a dyno run that they did, that the weld removed will give the 400 about 1/2 hp increase.
Question is how much hp does just a slip-on add and then 1/2 more with the welds gone. What is the increse with both a headpipe and slip-on (complet system)?

[AtvMxRider]

I did mine but honestly I can't tell if it made a difference or not.:ermm:

[Chanman420q]

ive heard that if done right u can get power equal to an E-series.......:o

[Woodsrider]

I have groung the welds down on mine and four others for freinds, three out of five of us notice the gains:ermm: It aint much, but I felt it was a gain that was worth the effort.

If the welds are more than a 16th of an inch tall, all the way around the inside diameter of the pipe, this is a substantial restriction considering the pipe is already so small.
I know my welds were easily 3/32" tall, and I opened them up to near flush.

[stiffy]

Pappy - Do you know about how much it costs to get a stock 400ex head pipe ceramic coated?? Thanks - STEF