Hey yall,
I'm new to this particular forum so I suppose I should tell you what I have and how I ride. I own a 400ex. Mods include- 87mm 11:1 JE piston, a middle-of-the-line port and polish, White Bros. Pro-Meg full exhaust, and a K&N. I live in Las Vegas and I ride WOT all day. My plans with the powerplant are to eventually get a larger carb, finish up the port and polish, get a different rev box, and when the JE piston goes limp- Big Bore. I didn't mention a cam because that's what I need information about. Can you guys tell me the difference between the White Bros. recreational cam and the XR cam? How much of a performance gain will I get from either of these with the mods that I have? I looked up the HRC cam at service honda a few days ago and thought it was a little too pricey and I also thought that it would stand a strong chance of breaking off a valve. I don't want to sacrifice reliability, but I do want as much power as possible. I also just read the post about the HRC cam on this site and it sounds great, should I fork out the bucks for it concidering how I ride? And what about web cams and GT Thunder? Which cams will I need to get new springs for or hardened rockers? I know that I'm asking for heaps of info, but little bits at a time will help also. So whatever knowledge you may have is more than welcome. Oh, and Gabe, you seem to know alot about the 400 and so far I've agreed with everything that I've read of yours, so I'm particularly interested in the book I'm sure you'll write once you've seen this post. He he he, If you have'nt noticed, I write books too.

 

Hello? Does anyone have any answers?

 

From what I have read if you go any more aggressive than the GT Thunder play cam or the XR400 cam you will need stiffer springs. If you run a race cam it puts more stress on the rockers and also the cams are hardened so they beat up the rockers more. Powroll.com has a pic of what a race cam will do to stock rockers.

If you go with anything besides the GT cam or the XR400 cam. You might as well core your 400EX cam and get a race cam as opposed to the HRC. It seems as though the HRC is really high priced.

However, once you go with a race cam you are going to have to pay for stiffer springs and hardfaced rockers. I think it cost me about $200 for hardfacing and about the same for springs. I also have a stronger cam chain cant remember exactly what it cost.

Basically, you can get an XR400 cam for $150 or less with no core, or you can pay somewhere around $600 for a full race set up.

Sparksracing.com has pricing so you can get an idea of what it costs.

Adam Smith

99 400EX

 

Would the XR400 cam or HRC cam help more on the MX track? I'd like power throughout the powerband, but don't know which cam would work the best. Could you all help? Thanks.

 

Depends on the track, the XR should develop more bottom, the HRC probably more mid and top, with a little less bottom than the XR.

The HRC should develop more HP, since HP is a function of RPM.

Also look into the GT Thunder cam, over $100 less than the best priced HRC, and I've heard nothing but good about it. I'd say it would be more comparable to the HRC than the XR. Personally I've compared the two and the GT T cam has MUCH more high lift duration, just haven't gotten to ride it yet.

Also remember that when you raise compression, you can afford to go to a wilder cam.