Cam Cams Camshafts (400EX) information

[GPracer2500]

I see a lot of questions about 400EX cams. I thought this might be helpful. I picked up this info from various places...if anyone sees errors point them out. The Hotcams specs are straight off their website and I called them to get the specs for the old version of the stg 2.

The lift is how far the cam opens the valve. The duration is how long it leaves it open. The more lift and duration the more aggressive the cam. Big lift and duration numbers work best at high RPM while more mild numbers are best for lower RPM.

Also, the more lift and duration of the valves the more important it is to have a high(er) compression piston. This is because with high lift/duration there is more opportunity for air to escape through the valves as the piston begins its compression stroke. With an aggressive cam some dynamic compression (i.e. the actual measured psi of compression while the engine is cycling) can be lost. This must be made up for with a higher compression piston. An aggressive cam with a stock compression piston may actually perform worse than the stock cam because too much compression is being lost through the valves being opened so much.


cam: Intake lift; Exhaust lift; Intake duration; Exhaust duration

stock............... .316, .302, 234, 238

XR400.............. .326, .321, 240, 244
HRC................. .350, .339, 254, 256
GT Thunder....... .350, .345, 256, 256
WB Track.......... .350, .345, 256, 256
WB All Around.... .345, .335, 240, 248
WEB 450/451..... .350, .345, 256, 256
WEB 479........... .378, .378, 250, 250
WEB 463/9i....... .385, .370, 272, 270
Hotcams stg 1... .354, .354, 246, 246
Hotcams stg 2... .354, .350, 254, 248
HC stg 2 (old).... .348, .349, 254, 254
Hotcams stroker. .358, .354, 262, 257

Notes:

--Numbers are listed in inches and degrees of crank rotation (lift duration at approximately .050" lift).
--The Hotcams stg 2 old version is identified by "HCDG NO. 08" etched onto the cam--not sure what the current version says.
--White Brothers All Around is etched with "WB1870".
--White Brothers Track is etched with "WB1498".
--Notice that the WEB 450/451, GT Thunder, and WB Track are all the same grind.
--Honda part number for the HRC cam (it's actually an XR400 HRC cam) is 14000-NKK-000. I don't think they are still available from Honda.

[coryatver]

Thank you man. This should go in the HOW TO section

[mrnate400ex]

this is some excellent information!!!! do you know any info on the magnum cams?? where would they rate?? thanks!!

[GPracer2500]

Originally posted by mrnate400ex
this is some excellent information!!!! do you know any info on the magnum cams?? where would they rate?? thanks!!

I can't find any info on Magnum. If you (or anyone) has got a link or some specs I'll add them to the list.

[mrnate400ex]

no dice on the info on the magnum. colby from c&d said that the stage 2 magnum was a copy of the web 479 grind only a drop in version. that is all i have heard about the magnum. from what i gather in the specs the web 479 is the most aggressive cam on the list besides the 463/9i cam. so the 479 grind is a very top end cam?? i'm just making sure i am getting the info right. thanks.

[GPracer2500]

The WEB 497 does indeed look to be the second most aggressive behind the WEB 463/9i. WEB says this about the 497:

"Performance profile increases overall power. Designed for use with a racing piston and exhaust. Must use spring kit with shortened valve guides. Compression release removed. Hardwelded rockers highly recommended!"

I'm assuming requirement for shortened valve guide stems is because of the radical lift numbers. I bet the valve keepers/retainers would contact unmodified valve guides because the valves are being pushed down so far.

[mrnate400ex]

that makes sence to me. however, the magnum is claimed to be ok to use with the stock springs and rockers. would there be any damage to my head if i used the magnum stage 2 without the shortened valve guides?? i guess i'm assuming that the magnum is based on the same specs as the 479 grind. the 479 grind sounds to me like it is what i am looking for, but i don't want to have to spend all that money hard facing my rockers and changing springs and the valve guides and such. however, i don't want to sacrifice reliablity just to save money. i wish we knew the exact specs on the magnum cams, then we wouldn't have to question these things.

[Snipe]

bump good info the sticky to this is awesome!

[416exman21]

magnum stage 2 this is all i could find
intake Exhaust
Valve Lash: .004 .006
Valve Lift: 0.378" 0.378"
Duration: 274° 274°
Duration @ 0.050": 250° 250°
Lobe Center: 107° 107°

i also have a thread for hotcam 1-2 vs. magnum 2 just too see if its worth the change