klx400sr big bore kit

[klx400sr]

Which big bore kit should i get. i have a few mods and am geared high for highway use. I go back and fourth to school and work. im interested in a 470 big bore stroker or a 440 big bore or whatever size you guys recommend. Im on other forums for my 750 brute force and when i had my 05 brute i didnt know what was good to buy and i took it to the local stealership and they got every penny out of me for junk parts that didnt do anything. Im glad I found these forums because it seems like everyone runs about the same stuff and the people on here know what there talking about and know what works best!! thats why im here and asking you guys what to do!!!

i got a $1400 spending cap for now. what can i do with it? i just ordered last week: Twin-Air filter, FMF Powercore 4 exhaust, amsoil, 16/41 sprockets, good x-ring gold plated chain, jet kit, enduro 30/70 street tires, hand-guards, and 2inch lowering kit.

Will a 440 bbk be unreliable? i do alot of open highway riding (75-90mph) this past summer it was all stock and could hold it around 80 for a good 2hours commuting from my moms house to my dads (im 17) i want the same reliability i had from stock. it has 16k miles on it currently i parked it at 15994 and decided to go big. will i notice a big gain from just a new cylinder, 440cc piston, and 3 layer head gaskets? <-- anyone got a link to a cheap reliable good brand kit thats as easy as bolting it on and tuneing the carb?

any help is appreciated!!!

[007kfx]

this is the namura kit. Kawasaki kfx 400 Big Bore Cylinder Kit 440CC 03 - 06 | eBay....1/2 the price as the rest of them I have read good reviews about it,I bought one for my 462 build,...ended up ditching the piston for a CP piston do to clearence issues,... but if you do a set of "MILD" cams with a carb upgrade that will increase the power your looking for....the BBK by its self will be a subtle change without the supporting mods to go with it.....Not quite sure on what carb came on that...mik CV36,probably.........if your looking for best results find a FCR of some sort...its "NOT" mandatory but will help alot the stock carb can be made to work with a jet kit and so on....the cams will feed it the air IN&OUT that it will desperately need......And you had mentioned a "FULL" exhaust thats a good choice over a slip-on....The header makes the difference.....as for the reliability goes,As long as its not half-@$$ed you will be fine...do your home-work when putting it together and you will be fine.....make sure everything spec's out when you assemble it......

[CFM-Z440]

Like he said, the 434 kits are hard to beat for the cost and they are very reliable. The 440 kits have had some issues. The Namura or the Cylinder works kits are both really cheap. The piston in either one would be fine for what you're doing. Another good option is to send your stock cylinder off to Millenium Technologies and have it bored and re-plated to 94mm, and buy what ever piston you prefer. (this is basically the same thing as the 434 kits mentioned above, and will cost about the same). I would put the rest of your cash into other performance parts. A 12.5:1 434 kit with exhaust system, and some mid sized cams, and a dyna ignition will really wake that thing up. I'm talking like a potential 10hp increase over stock if that bike has an FCR 39 on it already. If not, add that to the list. For cams, I would highly recommend Web 536/540 grind cams. They don't offer them that way, but you can ask for them that way. If you can find some used old style hot cams, they would be a good choice also.

The 470 kits are not so easy to accomplish anymore because Hot Rods stopped offering the +5 crank. They now make a +4 crank, and what used to be a 470 is now a 462. The +4 crank does not need a special stroker piston, or a spacer plate, but it does raise your compression by about 1 point over whatever the piston says it would be. You need to concentrate on keeping your compression around 12.5:1 or less on pump gas. If you go with a stroker crank, you will want much larger cams. Web 540/539 or larger. Porting and oversized valves would also be smart at that level, but we're starting to talk quite a ways outside of your spending limit.

[klx400sr]

thx guys. i was in the middle of mod my bike or mod the new brute i went with the brute bc i know alot more about them and i went 840 big bore with ceramic coated pistons, rods, bearings, radiator etc.. im going hard core on ceramic coating as my machine runs hott. this summer ill have a good source of income and will do the bike then. ill be seeing you guys in late april.

thanks for the info and im a hog when it comes to forums!! by then ill have a good bit of knowlegde on this stuff and will be back and i for sure want a crank and rods and top end done.. i dont want to redo the top end and then my bottom end go. i ran it hard and i dont want a rod bearing to go.

c-ya. you can find me on mudinmyblood or kawieriders.com (username: 2011bruteforce750) both are great sites and i think the kawieriders will be able to help any of you guys out if ur looking for a second opinion on something.