OK, got a good one for the gurus!! I have a second 350L that evidently is mis wired. If you turn the ignition on, the fan automattically turns on, sometimes if you hold the throttle a little bit off shut, it will start and run fine, but when it contacts the switch inside of the handle bar thumb switch, it dies. and last but not least, sometimes if you put it in reverse, it will die. It will not start in reverse during this time either. Now all of this said, sometimes except for the fan being on constantly, it will run fine like that there is no issue. I know that I can take the hood off of my other one, and trace and compare all of the wiring, but was hoping that someone may know off hand which wires to start with to narrow it down.

 

if i understand you correctly.it IS supposed to die when the contacts touch on the thumb-control,try adjusting the gap ,on the contacts(1/16"-1/8"),this adjusted thru the throttle cable,but you must have idle speed set first.
With the fan,check all the wiring running from the temp.sensor, but it sounds like the temp. sensor(should be located at the top of the radiator) itself has gone bad. easy check with a ohm-meter,turn key on and with engine cool,unplug connector,hook tests leads to sensor and you should not have any resistance.
i think you need to have the brake lever pulled to make the crank circuit work in reverse