cam ?

[dirtmomma]

WEll we put a 426 kit in our 400ex awhile back & we used a XR400 cam, what i'm wondering is when we adjusted the valves we did them to stock 400 specs is this correct??? Or should they be adjusted differently? It runs fine, but seems like something is hitting in there :( Would it be better to put the stock cam back in it?? The xr cam i bought used, seems to be in decent shape though just looking for suggestions cuz it definetly doesn't sound right, ticking pretty loud
Thanks for the help :)

[wilkin250r]

Are you using the stock 400EX valves? If so, I would imagine you would use the stock 400EX specs.

The whole reason you add a small gap between the rockers and valves is to allow the valves room to expand due to heat. This is why you always adjust the valves when your engine is cold. As they heat up, the valves will physically get longer. The actual amount that they will expand depends on the type of metal the valve is made of, and has nothing to do with what type of camshaft is installed.

[dirtmomma]

yes everything but the piston/cam are stock!! Thanks for the answer :) maybe they just need to be adjusted again after break in.

[cals400ex]

i can't promise you anything but i bet close to stock should be right. i know the more aggressive drop in cams usually require .005 and .006, which is 1 thousandth larger than stock on both intake and exhaust. i would make sure you timing chain is in good condition and that your timing chain tensioner is retracting properly. the stage 1 hotcams are really noisy, actually the loudest cams i have heard. i don't have any experience with the xr cam though.