So you already have a full exhaust and intake? How about that carb? If not you will be wasting your money.
That would be the minimum of what you want before going big bore.

 

Yes i dont want to spend the money on the carb or valve springs i just want to get cyliner works 435 kit that all you do is bolt on and hotcams

 

you can do that, but you wont see a quarter of the potential gains without a carb.

you'd be better off getting a carb and a high compression piston with your stock cylinder. maybe cams too.

oh and if you get the cams and rev box without spending the money to do it right with the valve springs, well, see what happens when your valves float.

 

exactly...........

 

i pulled 38-39 hp on a stock carb and it was stock bore to, the fcr really only bumped the hp by one , the real power is in the head ,intake and pipe. never floated a valve either how ever the drz springs are better

 

Cat, I completely respect your knowledge...
but what would you spend the money on....big bore kit or carb? I did the bbk first because I was more intimidated by dealing with the carb. Spent twice as much doing it though. They both have their benefits in different ways. For either you would probably want head work done to get the most out of it.
My wifes quad (04 Z) has a rev box on it and stock springs (well as far as I know) and it has not been a problem. She doesn't ride it hard though but when I tear it to do her valves this summer I will put in some drz springs that I already have laying around. She's starting to get a taste for some of the big Glamis hills....
For the kid though I guess the point was if he is going to have the head off doing a bbk then he should do the springs at the same time.

 

a bigger bore is going to want more air and sucking more air through a 36mm carb is going to hurt in the top RPM's, and felt more if a cdi increases the rpm's, thats also when the drz spring are needed. more so if 2000 rpm's are added
thing with the carb ya can wait and find a used one at a great price ,not so easy to find a used bbk thats not worn out .
my self i wonder why guys that want to go bb dont go BIG BORE, your never going to be happy
till ya have all the power you can get.
head work does make a difference, and not much has to be done, surprising what a good cleanup will do.

other than that ,are the things that wear out in the head like the valves , best ones are from RHC, yes they are more expencive but they dont wear out.

 

If you are worried about $$, I watched Ebay for a few weeks and ended up with a used one for $75, work already done (they were parting out). All I had to do was pop it in there.

Risky I know... but all is well a year and a half of hard riding later.

Just my two cents.

 

Hi I'm new to this but I have a 2003 z400 all stock I was wanting to go bigger but not sure what I wanna do will do that I was thinking bout a 440 bbk was thinking bout the fcr40 or 41 carb drz-e valve springs cdi box muffler timing chain cams and was wondering if my bottom end will be fine and what I all should do so it's fast and reliable any input will help thank you