best 400ex big bore kit?

[dirtyrooster]

I have a 2000 400ex and was wondering what big bore kit is the best bang for my buck. Iam 5'9" and 220lbs. ride mostly at the local sand pit and trails. which is most beneficial to me 416 426 440? any insights would be greatly appreciated. OH! almost forgot I am also planning on ice racing it. Thanks :confused:

[CJM]

This should be in the 400ex section...

Anyways, you could just copy what i did in my signature. Plenty of power for most. Power isnt so much bore size-its compression, more compression more power.

As for bore sizes, Id do a 407, its a tad smaller than a 416-but if you ever have to rebore it to a larger size you can then bore to 416, then to 426 if that wears out. A 440 you need a special sleeve and it cannot be bored at all. Biggest killer of the 440 is the heat they generate, they need to be kept cool with aftermarket oil coolers and a fan on the oil cooler-otherwise the engine will fail.

What will help you go even faster wont even be more power, you want better suspension. Just putting on a pair of honda 450r shocks will make a world of differance. If the suspension handles better you can go faster.

[dirtyrooster]

Thanks! I got caught up in the big bore hype and completely forgot suspension. I also heard that putting an 05 450r carb on it will help too. Any ideas on that?

[CJM]

Yes, the 450r carb helps alot. I havent ran one yet but have one sitting waiting to go in when I rebuild this winter..

Right now with the EX carb my 416 is quite fast. I mean its not gonna be a 450, but it can hang with them pretty damn well. For me at this point Ive ridden it like this for so long that I kinda want more power of the 450 lol-but what keeps me on the EX is its like a tractor. I can idle along if I want to and be perfectly fine. The lowend torque is dang impressive with my setup as well.

Remember, compression is power. Higher the comp ratio the more power. 11:1 is about the highest you can go without having to use 100+ octane.

Course going faster suspension really helps. Those 450r shocks will do wonders, if you have some money to spend have them and the rear redone for your riding style and weight and it will ride 100X better.

[dirtyrooster]

Thanks man! you've been a big help!!

[CJM]

No problem.

Start a thread in the EX forum if you need anymore help.