Electric Start Change:
Cut the wiring harness atleast 6" from the switch because the cable are spliced into two wires closer to the switch. Once, the wiring harness is cut you will find two orange colored wires. These two wires need to be connected to each other. Then you will find a Yellow wire that is the battery wire. The YZ250 Stop engine button has two wires. Connect the one wire to the two orange wires and connnect the other wire to the Yellow wire. Wrap them up good and you are done.
Choke Change:
You need to buy several DRZ parts. I don't have the part numbers handy, but I now which parts. The parts required are the Plunger, Nut, and rubber boot. The spring from the Z is reused because it is stiffer and will keep the choke from opening up on its own. The installation is easy just remove the choke cable and nut. The remove the Z Spring and put it on the DRZ plunger. screw the DRZ nut onto the carb until tight then install the rubber boot to keep dirt out. Your done. The only problem is that you must manually hold the choke open will the quad is warming up because there is no stay on the Z carb to prevent it from returning since it is spring loaded. The lever on the DRZ doesn't work on the Z because the carbs are slightly different.