Big bore options.

[luke23]

I am planning to rebuild my z400 for racing this year. I am debating on either the yoshimura 450 kit or the max power 455 kit. Does anyone have any experience with these kits? Price wise the 455 kit is a little cheaper but i want a very reliable motor that i can race on all year. I plan on putting an Edlebrock carb on it as well. The yoshimura kit comes with cams and a heavy duty clutch. I race xc in a local series and some national races. Thanks!

[cataway]

i cant speak to those kits but if you want a stronger holding clutch

check out the drive plates for a trx450r they fit and theres more material on the face for a better footprint on the driven plates, one more trick is to get 6 springs from a trx400ex (ex uses 5) so you get a much stronger squeeze on the clutch plates

[knoxville9]

Edlebrock carbs are notorious for sticking wide open when the slide sticks, just so you know that. I would personally go with and Curtis Sparks

[jonboy]

Sparks uses a Fcr39 carb Which can be had from a yfz450 cheaply off ebay or some other sites. Me personally I would go with the Yoshimura kit. They did a butt load of R&D and testing on z400 motor. And have it down pat for reliability

[luke23]

Ok thanks im going to start looking for one. From what little ive read there is nothing special that you have to do to install it. Am i correct on that? I plan on running a HMF or a Yoshimura pipe with it.

[cataway]

could i get ya to check out a barker pipe ?

[luke23]

http://www.exriders.com/vbb/showthread.php?s=&threadid=426365

If there is no specific year or model carb this carb should work right?
I will look into a Barker pipe. Never heard of them before.

[cataway]

yep thats the one , i would recommend taking off the tps ,its easy to do. what may be called hard is doing the idle adjustment mod . there is a wright up on it .

you may find the thumb pull may be a little stiff if thats the case there is a lighter spring you can get off ebay

[jonboy]

I have a few taps to do the Idle screw mod.

[luke23]

What exactly is the idle screw mod? I have heard of it before but dont know exactly what it is.

[cataway]

http://i44.photobucket.com/albums/f9/cataway/9-21-2007LS025.jpg
http://i44.photobucket.com/albums/f9/cataway/9-21-2007LS026.jpg http://i44.photobucket.com/albums/f9/cataway/9-21-2007LS022.jpg

what you do is take the idle adjuster off your stock carb ,drill & tap a hole ,and grind to fit the hold bracket ,your going to need a longer screw
to hold it on ,i suggest getting 4 Allen head screws way better than the Phillips headed ones

[airmobile101]

Originally posted by luke23
I am planning to rebuild my z400 for racing this year. I am debating on either the yoshimura 450 kit or the max power 455 kit. Does anyone have any experience with these kits? Price wise the 455 kit is a little cheaper but i want a very reliable motor that i can race on all year. I plan on putting an Edlebrock carb on it as well. The yoshimura kit comes with cams and a heavy duty clutch. I race xc in a local series and some national races. Thanks!
Run a 440 kit and be done with it. Anything else your pissing in the wind. Your really pushing the reliability of the engine past 440(94.5mm). Since you run XC, your gonna spend most of your time in the extreme high RPMS between 1-3 gears. In return, causes pre-mature failure in higher CC engines. Don't use a Eddy carb, they are junk. Get yourself a 39/40mm FCR carb. But only do that if you plan on NOT RUNNING a Rekluse. Otherwise, your gonna bond with the tree's;)

[miles Machine]

second what air mobile 101 says, run 39 for more power if you left the engine stock with out the bb id advise against it because it will shift the power high in the rpm range but since your doing the bb it will be more linear...i dont think youll need the rekluse tho it will just take some getting used to.

[luke23]

I decided to go with the yoshimura kit. It's a stroker 449 and I think it will be plenty reliable. I'm going to get the sparks fcr39, exhaust and air filter. Hopefully this will be a good set up. I talked to yoshimura yesterday and really liked what they had to say. I'll be ordering it early next week hopefully.

[miles Machine]

i personally like strokers more the only thing you have to worry about with a big stroke in the load it puts on the front and back of the piston and cylinder wall...they typically wear faster

[luke23]

Yeh I like that it's a 92mm piston and a +5mm crank. It seems like a great deal. Considering the max power kit cost around a thousand and it only comes with the piston but the yoshimura kit comes with the piston crank cams clutch and ignition for $1525.

[miles Machine]

well i have a shop here I do engine rebuilds mods and whole bike set ups like that so if you dont want to mess with it I will do the whole thing for $300...if not let ppl know id like to get my name out there or atleast on this site lol

[luke23]

Originally posted by miles Machine
well i have a shop here I do engine rebuilds mods and whole bike set ups like that so if you dont want to mess with it I will do the whole thing for $300...if not let ppl know id like to get my name out there or atleast on this site lol

I apprecaite it man but ive got a guy here who rebuilds motors doing it for me. Im getting a full set of Works shocks for it as well. The whole bike will get tweaked a little. Just trying to get it completely ready for 2010.