XR / 400ex exhaust differences

[SHIFTx450]

I really want to run a full Sparks on my xr400. Anyone know how different the 2 are, anyone ever try the XR exhaust on a 400ex or vice versa?

[SHIFTx450]

I'm also researching the whole harness and electric start thing to swap over.

I'm open to solicitations on racing head/motor/carb/harness setups if anyone is parting out any well built machines.

[slightlybent47]

The power is in the head!
Just replacing the exhaust wont do anything but change the sound.
Ok you may get 1 or even 2 HP but that's it. You will save some weight though!
In order to get the most out of an exhaust you must open every thing else up first.
Like, port the head, deck the head or up the compression, HP valves, cam and carb.
Once you do that, then an exhaust will really help out.

Leave the electrical stock.

[SHIFTx450]

The power is in the head!
Just replacing the exhaust wont do anything but change the sound.
Ok you may get 1 or even 2 HP but that's it. You will save some weight though!
In order to get the most out of an exhaust you must open every thing else up first.
Like, port the head, deck the head or up the compression, HP valves, cam and carb.
Once you do that, then an exhaust will really help out.

Leave the electrical stock.

Not at all what I asked... But thanks for your input.