rebuilding the top end

[gsxrkneedragger]

my z was running and then shut off and wouldn't start again so i checked a few things. long story short, i couldn't figure it out so i took it to my local shop and the guy found out why he fixed the problem and then tried a compression test and something else to see why it wouldn't start. he said it was only 56lbs of compression when its supposed to be like 150 or so and then did a leak down test to see why it was so low and it was only reading 20 lbs using 100lbs. he told me that my top end was shot and that it needs to be rebuilt. i'm going to try to do it myself. should be able to.

the question is, what should i get? i know the basic stuff, piston, rings, seals, etc, but what can i get relatively cheaply as for performance gains, like a 11:1 to raise the compression some. do the drz kit thing? even a big bore kit? the sleeve has a coating so it can't be bored out so it might need recoating. any help at all, or any thoughts or whatever would be great. thanks a lot.

[airmobile101]

If your gonna have it apart, then do the DRZ upgrade. Take a look at your cylinder base gasket, youll notice that it protudes out with a brass ring. That brass ring holds together three gaskets, replace that with a DRZ400 base gasket which is only one gasket. The DRZ400 has two springs per valve compared to the LTZ400. You might want to swap those out also. If your mechanically inclined, it shouldn't be an issue. Just make sure you set your engine at TDC before tearing it all apart.

[cataway]

you should defiantly replace the cam chain ,go with a D I D ,your going to have the jug off and i cant think of a better time to make
that improvement . changing the intake valves is a must, I'm not going to say what valve to use but i will say stay away from ferrea
unless you get the special hardened ones ,regular ferreas are way to soft and your only going to get a few hours out of them.
have you thought about a set of hot cams ?

[gsxrkneedragger]

a few questions about what you guys said so far.
1.how do you set the engine at tdc? i'm sure its in my manual but don't have it with me right now.
2. just get a drz base gasket? thats all. whats the benefit of that along with the valve springs?
3. how much are the intake valves and what would you recomend brand wise, being cheaper but decent?
4. i thought about a set of hot cams but don't know too much about what they do performance wise and reliability wise. what do you think?
5. where could i get a cam chain at a decent price?
6. what about the high compression piston? i don't have anywhere around me to get race gas so i can easily only get 93. could i still use one, or would it not be worth it both performance and reliabilty wise?

as of right now, my quad only has a k&n filter. i plan on getting a full yoshi rs-3 system at some point in the near future along with a jet kit.

thanks for the help so far. keep it coming. i'm looking forward to starting this in a week or so and start getting the parts soon. thanks.

[288sunny]

Im in the middle right now of having the DRZ kit installed, well worth it, instead of a single spring itsa double, which helps, specially when your heavy in the upper RPM range for any length of time, plus if u do the big bore kit, your just that much more ahead! the DRZ base gasket is a single layer, oppose to the z400 which is triple:( so it bumps the compression a tiny bit, from what i hear its not enough to notice, however you'll have a much stronger upper end!

As for the High compression piston, i as well had one ordered, its suppose to be here tomorrow and was going to have it put in, Until i found out you have to run race fuel or a mix of 100 oct. & 93 Oct. So if thats the case, its out, id rather have the big bore kit!

[gsxrkneedragger]

forget that mixing gas crap. i'd much rather just pull up to the gas station and throw some gas in it and go. where did you get your drz kit at? and is it just the base gasket and the valve springs?

[288sunny]

You can buy the whole kit ready to rock from advantage cycle,
http://advantagecyclelc.com/index.php

Or you can have your local dealer order the parts, or you could from any website, its basically DRZ valve springs and base gasket, D I D cam Chain, you'll need the Clutch cover gasket as well, you could look at advantage's website and go from there, kinda price compare, but i think getting it straight from him will be the cheaper bet. And i agree dont want o mix gas, thats insane!

[gsxrkneedragger]

288sunny, thanks a lot for your help. i'll let you know when i start this and see what happens.