Just bought a 2001 yamaha yzf 426 how do start

Have a look here in the second post in the thread. Great video showing how to do it:

http://www.thumpertalk.com/forum/showthread.php?t=447989

For a cold start, turn fuel on at fuel tap. Pull out the choke knob. slowly kick the kickstarter until you feel it become harder(more resistance). push past this resistance then release the kickstarter. What you have done is put the piston in the position just after top dead centre of the compression stroke.Now give it a big kick whilst opening the throttle slightly. There is a real techneque to it so don't think your the only one who has problems! Otherwise, ask your local Yammy dealer for a look at the owners manual. It has a description on how to both hot & cold start your bike. They may let you photocopy it. Good luck.
If it just isn't happening try removing the sparkplug,put it back in the plug cap,rest the plugs metal body on the cylinder head (don't hold it there or you could get a nasty shock) Now kick the kickstarter while watching the sparkplug gap. Did it spark? If it didn't theres a problem. No spark means it wont run! Then you'll need to find out why theres no spark. Hope this helps to get you started Otherwise let us know and i'll se what else I can suggest.

Hi there,
I had the same problem and nearly sold my bike due to it. What I do and this is my option as there are many out there.
Cold start
Fuel on, choke out fully.
Rotate the kick starter until you feel the pressure.
Then pull the decomp lever in slightly, until you feel the pressure off the kick starter.
As mentioned before the bike is ready to start, keep in mind no open throttle as this will flood it.
With one BIG motion, kick start the bike.
It should start on the 1st or 2nd kick and you will be away enjoying the nice machine.

Cheers

Keep in mind that it has an accelerator pump and squirts a big stream of fuel every time you twist the throttle. No one should tell you simply "open the throttle slightly'' whilst kicking. After a couple kicks, you would have it completely, hopelessly flooded. This is the most common reason for new owners' inability to start. After the first squirt(if needed) it's best to put the throttle hand on the throttle housing (off of the twist grip) to avoid opening the throttle each kick. If it becomes over fueled, leave the throttle closed and pull the red hot start button, then kick. Failure to start will be the result of too much fuel or too little fuel and you will have to learn the appropriate procedure for the particular bike and temperature. The de-comp lever and kick procedure is another story in itself. I highly recommend putting in a Hot Cams exhaust cam with auto de-compressor to make your kicking drill much easier.

Dont open throttle at all not needed just decompress few kicks then give it a good kick start really easy

Don't forget the decompresser lever on the left side handle bar, you need it to push past top dead center as the auto decompresser didn't come out from the factory till 2003

It is quite simple, just turn on your cold choke (black) and petrol tap. then pull the decompression cable in and give it about 10 full kicks (this should be very easy) and then on the 10th kick release the kick start up slowly to about half way. then release the decompression cable but keep the kick start where it is. apply the throttle for 2-3 seconds and put all your weight into the next kick. if it does not start first time then it will almost definately start second time if there is no problems with it