After buying the  aerox 155 I didn't bother to sell my  nouvo 125 sx  so I just kept it as a spare run-around 

 

Took it out few weeks back and hit a rainstorm with  sections of road like rivers but kept the revs high and got through it without stalling but the water was nearly up to my knees and hitting in waves as faster traffic passed (felt like jetsking) ?

 

2 weeks later it still started but with a bad vibration noise+ judder on acceleration so I parked it until I had time to take to yamaha 

 

  today it started then died a few seconds later and on the next  20+ attempts won't even kickstart, display is flickering and  and the yellow engine warning light is on for the first time ever (as pictured) 

 

 

 

I was hoping to ride it to the dealer  (22km) but now that's out of the question 

 

I will change the oil, sparkplug, wd40 the ignition etc and try to start it with jump leads tomorrow but if that doesn't work Is there anything else I should try at home ? 

 

(don't want to spend a fortune fixing a ~£400 bike but don't want to scrap it unnecessarily) 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Juddering you felt is probably light rust in the clutch after having been in the flood water it will go away if you ride it periodically. 

 

Sounds like the battery is dead.

 

Disconnect and reconnect any and every electrical connection you can find. 

 

Good Luck

After riding through what you described I reckon it's worth saving. ? it will go again with some TLC.