What the Best Bore it for a 2005 KFX400?

[takechances9]

id like to get some more power out of my 400 i was looking at the athena kit witch seems to be a pretty simple install does anyone have anyhting bad to say about athena or have any good recomendations for another brand? Thank!

[boyntonracing]

The bore kit is nice but honestly from experience, throwing in some valves, cam and high comp piston will bring your 400 alive! you will be amazing, my old 400ex beats 450's...

[timmersam]

If you are going to do the Athena make sure that you get yourself
the heavy duty cam chain. A friend of mine put an Athena in with the 12.5:1 compression and stretched two of the OEM chains like nothing. It was incredible the power he got for the 434 kit, cams, and a pipe. I ran it against my Houser CRF w/ 13:1, web cam, port and polish, and oversized valves, and he wasnt too far back...as long as he had someone else running the controls haha. If you do decide on the Athena pm me and ill send you a link to where you can get the HD chain.

Sam