Why do they have 2?

[400exc]

Why does the 400ex have 2 headers on it? i dont know i was just wondering why? for more flow or what? too bad it dont have dual exhaust tho, that would be awesome!

[Dannys440]

The 400ex has two headders because it is a 4 valve head, which means you have 2 intake and 2 exhaust valves.

[prepracing]

Originally posted by 400exc
Why does the 400ex have 2 headers on it? i dont know i was just wondering why? for more flow or what? too bad it dont have dual exhaust tho, that would be awesome!

you can by dual exhaust for the 400ex :devil:

[400exrider707]

Originally posted by Dannys440
The 400ex has two headders because it is a 4 valve head, which means you have 2 intake and 2 exhaust valves.

that is partially true. It doesn't have two headers because its a four valve, it has two because honda decided they wanted two. YFZs are five valve so how come they only have one header than bud?

[Dannys440]

liquid cooled? it would only have 2 headder pipes because they only have 2 exahust valves. like the raptor 660

[450robot]

uh, the 450r has 2 exhaust valves, and it has one header

its just the way honda developed the motor

[dunes_rider]

ya the 450r has 2 exhaust valves, and it has one header

And these header is big not like 400ex

[jsmith2232]

they do make a dual exhaust for the 400 ex , i'm not sure where i saw it or who made it but just start searching on the net. i beleive that it did require relocating the battary.

[theTman]

LTE

[yamablaster24]

just because they made it have 2 exhaust ports....