I just bought a 1997 XR400. Bike is stock except for a gutted exhaust.
Bike is difficult to start cold and needs about 8-10 kicks, hot it starts first kick every time. I just checked the jets - Main jet 162, pilot 62. I live at about sea level in Katy, Tx.

A few questions:

1.) I haven't had time to check the valve clearances yet, maybe the hard starting is caused by them being out of tolerance, or is my jetting wrong?
2.) Moving the choke lever moves the choke, but I expected full choke to cause a higher idle, but it doesn't - is this normal?
3.) I'm going to change the exhaust for a FMF Powercore 4 - what should I change the jetting to for that exhaust?
4.) What does the air cut-off device on the side of the carb do?

Thanks for any help

Stock exhaust? Gutted how, explain more please.

1. Yes, valve clearances will cause hard starting, as well as lots of other problems, but check them to rule them out.
Too low of an idle will do the same thing. Try turning up the idle with the black knob, 1/2 turn clockwise. Jetting is about right, don't mess with it just yet. Make sure the carb is clean.

2. Your using the choke correctly right? All the way down is off and all the way up is full on. You wouldn't be the first to get it wrong.

3. Don't change the jetting til after you install the FMF. Might not need to. You've done the intake mods, UNI filter and pulled the snorkle, to go along with any exhaust mods, right? If not, that could be one problem.

4. The air cutoff valve (diverter valve) prevents a lean condition when riding down the trail and you close the throttle, getting that pop pop pop pop. It diverts fuel from the pilot system during those throttle settings to prevent that lean condion when closing the throttle.

mine fires in 1 kick with this procedure:

turn up idle screw about 1 turn
Pull in decompressor/depress kill button/throttle wide open
full choke
kick 4-5 times (primes the engine)
release
kick w/ no throttle
don't touch throttle
go to middle position on choke & let idle
after a minute turn off choke and turn down idle

i also have done gordon mods, denso iridium plug & spark plug cap mod.

jetting:
0000 ft > 160 / 60
1600 ft > 158 / 58
3200 ft > 155 / 55
5000 ft > 152 / 52
6500 ft > 150 / 50
9800 ft > 148 / 48

as noted make sure the valve are adjusted correctly!