Looks like Im taking the plunge. 500cc BB 400EX

[marioweldinginc]

Im talking with 4ST about machining my 400EX motor to 500cc. From what ive read this kit is quite reliable. Hoping to get this done sooner than later. $$$$$$$

Any thoughts?

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[rappy97]

IMO, you would be way better off getting a 450r. That kits gonna cost some pretty good money. And it won't be reliable, atleast not like a stock 450r. I don't see that it would be honestly worth it.

[marioweldinginc]

The complete kit plus parts machining and labor is far less than even a wrecked 450. I was planning on buying a kfx700v instead but ididnt have the funds. Im figuring i pay as i go at this point. As far as reliability your probably right but im hoping that 4ST are professional engine builders

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[rappy97]

Figure this. Sell your 400ex, and use the money that you would put towards the motor. You should have enough to buy a nice 450R. You will have ATLEAST $1500 into the motor, and you could sell your current bike for seems atleast $1800-2000.

[marioweldinginc]

But then i would have just a 450r and not a 500r

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[rappy97]

No. Slap a 500ex kit on, it will not beat a 450R IMO

[marioweldinginc]

it might

[rappy97]

Maybe with a larger carb, good intake, and a good exhaust, and shave 40lbs it might. Chances are slim IMO

[marioweldinginc]

See :-)

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[quadnut20]

Im talking with 4ST about machining my 400EX motor to 500cc. From what ive read this kit is quite reliable. Hoping to get this done sooner than later. $$$$$$$

Any thoughts?

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Get the 450 instead !! you`ll be happier !!:yes:cooling it will be a problem !! the 440kits are known for having cooling problems imagine what a 500cc kit will be like !

[oxidized_black]

Get the 450 instead !! you`ll be happier !!:yes:cooling it will be a problem !! the 440kits are known for having cooling problems imagine what a 500cc kit will be like !

over heating will be a big issue

[marioweldinginc]

Got it covered. Bigger oil cooler and Spal fan.

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[marioweldinginc]

I dont have the money for a 450. If i were to buy a quad it wouldnt be a 450. Id get the kfx700. Went riding with a modified one and a stock one. A 450 wont even come close (oh boy here come the naysayers comments)

Anyway i am doing this build in steps. I priced it out and still going to be far less than a 450r

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[jerod400ex]

I dont have the money for a 450. If i were to buy a quad it wouldnt be a 450. Id get the kfx700. Went riding with a modified one and a stock one. A 450 wont even come close (oh boy here come the naysayers comments)

Anyway i am doing this build in steps. I priced it out and still going to be far less than a 450r

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Go for it man!!!! if you can keep the engine cool it will rip like no other:biggrin:

[marioweldinginc]

Part of the 500cc kit is a big oil cooler

Im hoping. Im working with Mickey Dunlap and he is taking the time to walk me through this. He is quite thorough.

[jerod400ex]

Part of the 500cc kit is a big oil cooler

Im hoping. Im working with Mickey Dunlap and he is taking the time to walk me through this. He is quite thorough.

well with his help u prolly will figure it out..... like i said if u can keep the temp just right it will run like a charm and rip like no other:yes:

[swampcat07]

No one ever asks for less power. I did a BBK on my quad and it has been very reliable. With a new to you used quad who knows what you are going to get. Stick with yours and add some HP. Good luck with the build. Post pics along the way.

[marioweldinginc]

Will do. So far after 6 months of hard riding I have no strange noises or motor issues. Ive heard the bbk are reliable but its usually the engine builder or the lack of propet breakin that kills it

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