Im looking at getting a new bike. I like the 400ex but i still want to keep up with my brothers YFZ450. And i dont want to be another typical YFZ450 guy I hear that the big bore kits for the 400ex is pretty sweet. What do you guys think?

 

400ex are great for trails. The 416 bore or 426 bore is best to do only when rebuilding in my opinion. A pipe/filter on them really wakes them up but, you can do whatever you want to the thing and it's not going to be a 450.

 

i have to agree with koopa.i have a 400 and have everything done except a bore kit and ill hang with any 450 in trails.but as soon as we get into open fields and straightaways,different story. 450 definitely pulls me through 5th man...

 

I have to ask what do you mean by "typical yfz450 guy"? There is so many mods/addons available these days if you want to stand out you can.

 

i have tried all three. the 416, 426 and 440. im happy with my 426. but im sorry koopa, my 426 will dust any FACTORY 450r. regardless of rider. lol. im serious shes a bad beast. try the 416 and if it blows later get the 426...you be the judge [img]i/expressions/face-icon-small-smile.gif[/img]

 

i agree, i raced a stock 450r a couple days ago and he only beat me by about a quad link. so i know if a 400 was bored it would wax 450's all day...

 

go with the 426 , i wanted that , but somehow got a 416 kit (shoulve payed attenion at the shop ) but mine aint right and im not happy with it , but ive rode a bad one that was stock & with more mods should atleast run with a 450

 

Thanks for the input guys. Huge help

 

<div class="FTQUOTE"><begin quote>Originally posted by: 400exrcr

i agree, i raced a stock 450r a couple days ago and he only beat me by about a quad link. so i know if a 400 was bored it would wax 450's all day...</end quote></div>

That's crazy talk guys. I had the 426 piped/filter 450R carb, bro had 416 piped/filter had 2 other friends various stages of upgrades on 400ex. Stock '07 yfz450 would outrun us all. Piped it was no contest.

Also, there is no power difference between the 416 and 426 that is notible. Were talking 10cc's here. Displacement alone with no head work to help will not be very efficient.

Don't get me wrong. The 400ex is a great machine and is far from a weakling, I loved mine but, after sitting on a 450 you'll know that its a race bred machine where the 400ex is a king of trails.

 

I agree with you Koopa. The 400 is designed for the trails. That's were its tuff to beat. Most people don't use the 400 in stock trim to its full extent. No tot mention, with aftermarket mods, pipe, and jetting, its an even better trail machine. The 450's, are designed as a high revving MX machine. Yes they can run in the trails, but you need to be on your game to make them work. You need to get them in the upper rpm's, where the 400 will lug all day, and put a smile on your face.

For me its the grin factor, not the top speed. Both machines are good, but I prefer the 400, but I am biased [img]i/expressions/face-icon-small-wink.gif[/img]

My 400 is due for a top end. Its currently still on the stock bore, with an aftermarket pipe, and jetting. Unless there's a problem with the cylinder, I will stay with the stock bore. I don't use the all of the power now, why bore it out to have more power that I won't use....

If its top speed you want, adjust the gearing by adding a tooth on the front sproket, or dropping 1 - 2 in the rear. The 400 with its lugability, can handle a little higher gearing in the tight trails.

Just my $.02 worth