XR cam in the Ex

[whipit1k]

OK maybe I will dig in and try to make this thing a little faster. I have a 98 XR400 sitting in my garage. I wonder if I would see a nice improvement if I try the XR cam? I also have some leftover XR top end gaskets. Is the XR head gasket thinner?


Honestly, If I do a 440 kit at 11:1 (did one on my old 1996 XR and wasnt that impressed) an XR cam and a pipe, will I at least hit 35 HP??

I am a little annoyed because I was riding in a few inches of snow and the thing has no torque or rev stock, and it constantly gets bogged down, yet it hates to be revved out

[bmw500hp]

There are several members on this site that have xr cams.. ask that question directly as i did,,, these guys are really helpful.

[99_400EX]

ive got an xr cam and like it if you added a cam to your Xr when you put the 440 in it you would of seen big improvement a good set up is a 416 kit for the 400exlook at my mod list all i need next is a nice big carb

the xr gasket is thinner and i am not sure about the 35 hp all i know is that my 400 wont keep the front wheels on the ground

[loganB]

Im haveing an xr cam put in right now the 400 is in the shop giting a weisco 440 big cor kit and an all around web cam.

[RytM1]

I agree with 99. I've got the XR cam with my 416 (10.8:1), and the combo woke the motor up nicely. I'm assuming it would work well with the 440 also. A lot of people will suggest the Hot Cam, and it does sound nice (but they were just hitting the market when I built up the 416). I am in the process of installing an FCR39, as soon as the throttle cable comes in for it.

[whipit1k]

what is the advantage to the 416 kit vs. the 440? is it possible to bore the stock sleeve to 416 rather than resleeving? Is that the advantage?

[swamprider7]

416 is supposedly more reliable than 440. 416 is also supposedly quicker revving. I don't know how true the reliability thing is. I think that who builds your motor, how you break it in, and how your motor is built are what determines reliability.

416 is stock sleeve, bored .80 over

426 is stock sleeve, bored .120 over

440 is re-sleeved with a 89mm piston

hope that helps.

[crazy canadian]

i haven't had any problems with my 416 and xr cam. runs real good. it definately revs real quick and i love the throttle response!!

[VegasEx'r]

I put in an xr cam when I put in a 416 piston earlier this year. It woke up the engine a lot, but it wasn't a great mid & top end cam (read: dunes). I put in the Hot Cam stage 2 when it came out & it made it a much better engine. Since you already have the xr cam, the price to get it can't be beat, but I would go with a 416 piston. The xr gasket is thinner, so the advertised CR should be more accurate. If you put in a 440 piston, I would not recommend the xr cam, and I don't think that the Hot Cam would be a good match either (I think it was 440ex4me - but I'm not sure - who put a Hot Cam stage 2 in his 440 & was not impressed at all). The 440 is big enough that you need a cam that has a higher lift & duration to really get a good, full charge. That means more money on hard faced rockers, heavy duty valve springs & cam chain, possibly shortened guides, etc. Plus a bigger cam from Sparks, TC or the like.