If you want big gains you got to have a deep pocket.
You should get a gain not sure what it will be yet,Ill know this saterday after I run it and make the adjustments.
I turned off my O2 sensors for now ,but plan on cutting one in just to play around with it. My bike will be for track use only.
The earlier 675's (06-08) seem to easier to make the head pipe because the exhuast ports are round in the head, the later 675's (09-11) have a D shape exhaust port so getting the pipe connected to the EX. port is to have something machined out to fit the pipes to.
Unless you are looking for peak HP then the head pipes should be good for all around use on the street.If you do go with big head pipes you lose some low end power that makes the bike fun on the street.
And no-one can see them anyway they are covered by the faring so you loose the cool factor.
You have to download the program from Tune ecu (Free) and get a cable ( 15.-30. bucks) and get a free download to open a HEX. file so you can see what is going on with the bike as far as errors and maps its a must and worth every penny if your going to play with making mods to the bike.
Think of it as a tool! It the cheapest tool I've bought in a long time that works great.
Man your lucky if your buddy is willing to make them and has a tubing bender on hand. i had to kind of guess the bends and order and get extra incase i screwed up. but it worked out.
Here is a couple pic's of what is clogging you pipe right now.:nod: