I heard something about a XR250 cam on a 400ex and it screams. Is this possible? If it is whats the whole process of doing it?

 

i think you mean xr400r. i've never heard anything about a xr250r cam. but i know a xr400r cam will work

 

You can use an XR400 cam, but you also can use the ignition control module from an XR250. I think it will let you rev another 1100 rpm past the stock limiter.

Changing the stock cam for the mild XR400 cam seems hardly worth the trouble since you have to remove the head. Changing out the icm is easy all you have to due is unplug the old black box under the headlights and replace it with the XR250 icm. It will take you about 5 minutes.

Adam Smith

99 400EX

Adam Smith

99 400EX

 

I wouldnt want the XR cam in a EX, My 96'XR400R has half the torque as my friends EX does... Pick up a real cam if your going to pull the head.

 

You don't have to pull the head, only the valve cover. It only takes a couple of minutes.

As far as torque.... I don't know on a stock engine, but I went to almost 11:1 with the XR cam and I have more low, a much improved mid, and more top, with the stock pipe.

The XR cam is similar to the web 450/451 grind for less money, still has the decompression equip, and you don't have to mess with the core charge.

The 96 XR has many carburetion & exhaust "issues" that were somewhat corrected in later years as well as the lack of an accelerator pump, which will vastly improve throttle response. You can hardly compare the two.

 

I appologize for giving wrong info. However, wouldnt you still have to take the front plastic and gas tank off to get to the head to take the valve cover off. It usually takes me at least 10 minutes or so to get that stuff off.

Adam Smith

99 400EX

 

Yep, it's still a very quick and easy job.