Need opinion!

[gclax1336]

Alright guys I have my engine out of my frame right now half way through a winter project and I figured I could do some mods as I go. Whats the smart way to go... With the athena 435 bore kit or go with a high compression and hot cams?

[Rockwell67]

I would recomend getting head work done and increasing the aggresivness of the cam. Maybe increase valve size. You have to be able to move air to make power. A high compression piston and big cylinder do you no good if you can't get the gasses out of your motor. Big cylinder and piston are easy upgrades after that.

[gclax1336]

see one problem with that I do not have the money to sink into head work and im not racing any day soon. Just need more power with easy upgrades.

[Rockwell67]

Understandable, but you are going to spend 500+ for a bigbore kit. With another 200 or so for a cam. That puts you right in the park of a pro port and polish. I am assuming you already have exhaust and filter. (If not start there) It's just been my experiance that if you start with the head you are not scrambling later to have your motor reach the potential of the big bore. Currently my bike is stock dis & piston with head work and valves and I am faster than my friends who went the other way. We spent similar $ doing it.

[gclax1336]

The kit i was looking at was say 600 dollars how much was porting and everything?

[Rockwell67]

John at Nmotion now JSR Performance did mine. I was refered by Jeff owner of Fullbore Innovations. I had a bent valve so I couldn't say for sure what just the porting cost. But I had Ti oversized valves all the seats had to be cut and fit. I paid right around $1300 for the Valve work and the Cam. The machine work on the jacked up valve work was where alot of $ went.

http://bigboremotors.com/index.php
316-733-1936 #
I'm sure they could give you a quote and some advice.

Hope I am helping out, I just know I was going to go the same direction you are looking and am very glad I didn't. My bike runs hard and pulls very hard lowmid to top.

[soyo]

the z400 heads flow excellent from factory! even gust and jones only hade a clean up, or mild port job done on there bikes! its not worth the porting on the z400 unless your just looking for every last ounce of power. you are on the right track with what your looking for. hope this helps!!!

another thing to remember is, not to many companies worked with the z400. so they may not have the right combo on the head work down. most people are working with the new bikes. it is a shame though, i loved my z450. motor work deffinatly open these bikes up! you can also look for a 400ex intake boot and filter. this is a cheap way to get more power from what you already have! what mods do you have now?

[Rockwell67]

Soyo those are great points I was not aware they flowed that well off the floor. Having Hondas the priorities are obviously a little differant.

[gclax1336]

Engine wise I have the basics. alba exhaust k+n filter jetted and a rev box. i was looking at lukesracing bore kit to make it into a 450 anybody here anything about them at all?