So after 7 years of hard riding Im about 99% sure its time for a rebuild with my z400 and am not really sure as to where to start looking for info on building this bike?

Right now the bike is lightly modded, jetted, full yosh pipe, and an air filter and moves. Its right next to 450's in the woods and ideally I would like to be able to pull on 450's but reliably. I know I could go all out with a high compression piston, headwork, carb, cdi box and do the whole 9 but know bikes of this caliber tend to get a bit "finiky" as far as reliability and all that good stuff.

I was hoping to really just rip the bike apart and just do a high compression piston and call it a day, this way the engine isnt super modified, Ill have a little bit more power and should still have reliability. I know if I do valves and all that fun stuff I need to worry about clearance with the piston and what not. Im looking for some decent info on what to do and how to do it so I have an idea on what im getting myself into. Any feedback would be appreciated
-Gary

 

Here's some tips for a z rebuild:
Don't use stock valves for the rebuild, get stainless valves.
Get DRZ-E valve springs they are able to sustain higher rpm/bigger cams then the ltz springs.
You want power buy a Namura 434cc kit, instead of a high compression piston and allows you to run pump gas instead of race gas. It comes with piston, new cylinder, and gaskets. Use the single layer gasket in the kit for a 12:1 compression ratio (runs on 91 octane)
Rebuild the bottom end too. You start putting more power though a old bottom and and you will break something very quickly. Replace the all the bearings in the bottom end and the crank to be safe.
Use a D.I.D cam chain, much stronger then stock cam chain.

My Z motor is at 462cc and putting down around 50hp and it's just as fast as any 450 out there unless it's a big bore or stroked motor.
Here's what went into mine:
Namura 434cc Big Bore Kit $300
Hotrods +4 Stroker Crank $254
Hotrods Crank Bearings $50
DRZ-E 400 Valve Springs $55
Bearing Kit $130
Gasket and Seal Set $100
Kibble White Stainless Steel Valves $125
Head Rebuilt with new guides and ported $450
DID Cam Chain $45
Manual Cam Chain Adjuster $45
Webcam 539/540 Grind Cams $400
YFZ450 39mm FCR-MX carb $90
Dyna Programmable CDI $254
I did most of the work myself except for the head so I didn't include labor.
It's a reliable combo and not overstressed in any way. I also rev it up to 10,500 rpm with no problems. I did have a head gasket fail after I first built it because I must of got some oil or coolant on the head gasket before I torqued it down so it didn't seal right. Other then that no problems with it at all since I rebuilt it 3 months ago. Alot of people run this build and have had years of reliable use from it.