XR400 cam/ Stock 400ex cam whats the diff???

[400exBro]

If honda made the 400ex the exact same(mabye some changes like startor) as the xr 400 doesn t that mean they are the same cams????

If they are y are some people dropping in xr 400 cams ????

[moto93]

Honda de-tuned the XR motor when they stuck it in the 400EX by using a milder camshaft so by using the XR cam in the EX you gain power.

[Tommy 17]

the xr cam has more lift and duration plus its the only cam shaft thats a straight drop in all the others u have to take off the decompression switch and put it on the new cam... i love my tc cam cost about 205 the xr costs 120$

[400exBro]

The 400ex has a decompersion switch????? where is it located???
and do i need to replace anything else?? i am dropping in a wb all round cam(same as the xr400 but is made for the 400ex) and i hope i dont need to cange to much on the bike for it to fit?

[moto93]

The decompressor is internal but you don't have to worry about it anyway (works fine without it). You will have to press the cam gear off the old cam and press it on the new one though.

[Leo]

The decompression release only activates if the motor is spinning backwards (kicking back) which is fairly important if your kickstarting the bike.. not that big of an issue if your pushing a button (hard to drive your knee through the bars with electric start!)..

I've got Sat-Sun-Mon-Tues off, a brand new XR400 cam, dial indicator, and degree wheel... Going to try and scrape up some hard numbers EX vs. XR camshaft. It finally looks like I'm going to be able to get all my parts in (piston/cam/etc..)

Leo

[Tommy 17]

have fun leo.... i don't wanna make a new post so i will post this here i was bored today so i got out all my old rockers and springs and stuff and i was lookin at the one rocker and it has a big chip taken out of it and the ohters all are fine and smooth i am wodering is this good ( i don't think it is but i have new rockers in my 400 now) and did i lost power bc of this...

[patrick delao]

The 400EX stock cam is a bottom end cam and the XR400 cam is a mid to top cam. I lost a little off the bottom but it made up for it in the mid to top range. With the XR cam its a drop in can and you don't have to harden your rockers. Hope this helps.