400ex cam

[onebad450r]

I just tore down my old 400ex, that a friend currently owns to freshen it up for the upcoming season. It has a 440 national kit built by TC racing. He really likes the way it runs but the cam is showing some signs of wear and I told him he should replace it, the rocker arms and the valve springs why we have it apart. The problem is that he doesn't want to spend $215 for the cam and a good core from TC Racing and wants to go with something similar in another brand for about half the price.......So I decided that I would get my handy dail indicator and base out and measure the max lift and duration from the old cam to compare numbers with other cams to try and get something similar. Knowing the numbers would not be exact because the cam was wore some.....The problem is that I am comimg up with .247" for the exhaust and .252 for the intake, about .100" shy of what every other cam I look at. I cam up with this by setting the dial indicator up on zero, on the base line of the cam and slowly rotating the cam until I reached max. lift.....Does anybody know the rocker arm ratio on a 400ex? For example on a small block chevy you take the dail indicator reading times the rocker arm ratio 1.52" gives you the actual valve lift....Can anybody throw in there 2 cents worth on how to determine the actual valve lift of this cam. Any help would be appreciated....By the way the cam is engraved TC National and the bubble wrap that it came in only states the valve lash and this cam is no good for a core since its already been welded up and reground, Exta $150 for a core charge

[cals400ex]

here is some info on a few cams:

400EX CAMS
BRAND & MODEL IN.LIFT EX.LIFT IN@.050” EX@.050” NOTES
STOCK 400EX .316 .302 234 238 OEM
XR400 .326 .321 240 244 BIKE SR
WB ALL AROUND .345 .335 240 248 SR
HOT CAMS STAGE 1 .354 .354 244 244 SR
WEB CAMS 479 .378 .378 250 250 HR,VS,VG
HOT CAMS STAGE 2 .346 .346 254 254 SR
HRC .350 .339 254 256 HOP-UP
GT THUNDER* .350 .345 256 256 SR
WB TRACK* .350 .345 256 256 SR
WEB 450/451* .350 .345 256 256 HR
WEB CAMS463/9i .385 .370 272 270 HR,VS,VG
(In order from shortest duration to longest)
SR=Stock Rockers, Valve Springs & Guides OK
HR=Hard Faced Rockers Recommended
VS=Stiffer Valve Springs Required
VG=Shortened Valve Guides Required
*SAME GRIND


just to let you know, my friend has one of these hotcam stage 1's that has been in his bike for under 5 tanks of fuel that he may be selling. he will let it go for a decent price too i have a feeling. just let me know if your interested. cal

[MIKE400EX]

The rocker arm ratio is about 1.4 to 1. I just went out and measured a HC Stage 1 and it was w/in .002" on I&E of what you measured, so I would guess that the valve lift on your friends cam is right about .350-.355"
BTW, you CAN re-weld and grind a previously welded cam.

I love this site! :D I just took the head off my 400ex and am in the process of porting it. I am also considering a new cam. This info is going to be instrumental in my decision. If there are any suggestions, I ride desert and sand. My best friend rids a Preditor too, and I would like to keep up.;)

[H_W]

Originally posted by golfman400ex
I love this site! :D I just took the head off my 400ex and am in the process of porting it. I am also considering a new cam. This info is going to be instrumental in my decision. If there are any suggestions, I ride desert and sand. My best friend rids a Preditor too, and I would like to keep up.;)

I would suggest putting in a high compression piston also. With my setup, I can stay with and sometimes beat stock predators. I can beat stock raptors and banshees almost everytime. I have actually only raced one predator. It was stock with the baffle removed and we were very close.

I noticed that in addition to your high compression piston you have a stage 2 hotcam. I would like to put in a 10.5 compression piston also, but it seems that only 11:1 is available. I also noticed that you have a standard bore. If your machine with a standard bore, 10.5:1, and stage 2 webcam with porting and polishing can keep up with a pred, then that is where I'll go. I was going to go 440, but now I think I'll go 426 instead. That way I don't have to send off my cylinder.

[onebad450r]

Mike400ex

Thanks for the rocker arm ratio. I noticed that you have the web 479 cam in your motor. What do you think of that cam?....I checked on the web cam but they also require a core charge and they specify that it not be a reground cam....thanks guys

[H_W]

Originally posted by golfman400ex
I noticed that in addition to your high compression piston you have a stage 2 hotcam. I would like to put in a 10.5 compression piston also, but it seems that only 11:1 is available. I also noticed that you have a standard bore. If your machine with a standard bore, 10.5:1, and stage 2 webcam with porting and polishing can keep up with a pred, then that is where I'll go. I was going to go 440, but now I think I'll go 426 instead. That way I don't have to send off my cylinder.

Yea, I would suggest going with a 416 or 426 kit. That is what I want to do to mine, but I am saving up for a 450r.

[northeast400]

Web 405/451 I have found to be best

[MIKE400EX]

Onebad450r,
I like the 479 cam because it seems to pull as good as the 450/451 type cams on top but with a lot more low & midrange power. Going thru the woods I don't have to feather the clutch or shift as much & when I get to the open areas it hauls on the top too. I did have the 450/451 before, and that also is a great cam for mid and top end power just more tiresome to ride in the tight areas.
All the 400EX Web cams are welded and re-ground.