Are the handlebar switches gronded to handlebar??

Well i can now confirm that the "burnt electrical wiring smell"  was indeed the plastic i found melted on the exhaust bend.After cleaning it off the smell is gone 
The strange thing is that this is the first thing i checked when it started to smell. i seems the plastck was invisible/clear before after some days and it got a brown color.
I been wrenching on bikes since i was 10 bringing a 50cc vespa piaggio engine into my bedroom so mum got unhinged .im now 57  so it is a little embarresing i started taking apart switches and stuff haha.

 

How did that plastic end-up on the pipe? Hit a floating plastic bag riding, ha.