2001 400ex buildup

[Kawboyz beware]

My buddy has a 01 400ex that has a jet kit and wb exhaust and rev box. the top end is all stock I would like some suggestions of what to get this so to be 416 11:1 or the 12:1? what about gaskets? Timing Chain ? What cam ? Brands should i look at ect

my signature...if u want ur compression to be 11:1 run xr gaskets with the 10.8:1 piston

[cals400ex]

i like the 406 and 416 because you still have one or two more bores left on the stock sleeve if need be. they also produce less heat. you won't want to run greater than 11:1 compression unless you will be mixing race gas. i don't recommend the wiseco pistons. the je and ross are suppose to be better pistons. i have a ross and i am pleased with it. i am running a stage 2 hotcam and i really like it. many people on this site really don't like the hotcams because they use to have a flaw in their design, but that is fixed now. this cam allows you to use your stock rockers. the non-drop in cams require hardened rockers. the stock timing chain will work with a set up like this. some people just go ahead and put a new heavy duty one in while they have the engine apart. i left my stock one in. i am running cosmetic gaskets. i have not had any problem with them. just don't get a paper head gasket.

[Kawboyz beware]

should he get a degree flywheel key also?

So basically He should Get a
Je or Ross Piston 87mm 11:1
XR top end Gaskets
crf450 timing Chain

As for the Cam
new valves most likely and stronger valve springs

[cals400ex]

the key is not recommended for high compression.