OH I know its because when you rip out all of you electrical to save weight you loss the ability to flash the ECU on the bike. I know this as I tried to help you back then.
You are wrong on this point, sort of.
Yes, back then, last fall, I didn't have programming functionality figured out on a non eStart bike. Actually, I knew what to do, I just didn't do it because I was only going to ride the bike a few more times before putting it away for the winter.
I now have it figured out. To program a non battery equipped bike you just connect a 12V source to the bike's main harness. IIRC the brown wires are the switched 12V. Connect a battery to that and to GND. The fuel pump will run momentarily. Then use the programmer or the FI tool. They both work using this procedure.
On the FI YZ450Fs the fuel pump doesn't run when the tools are connected. It seems the ECU doesn't enable the fuel pump unless the engine is turning over. With the WR, the fuel pump starts as soon as power is applied, thus when you connect one of the tools, the fuel pump tries to steal power to run from them and it doesn't have enough capacity for that, so they shut down.
So the solution is to carry a small 12V battery and connect it to the bike before doing any programming.
And, for the record, I didn't rip off any harness back then. Everything electrical remained totally in tact until recently when I removed some connectors from the front of the bike to make the harness easier to move out of the way.
Edited by MidlifeCrisisGuy, September 15, 2014 - 05:07 PM.