Fork oil is compatible with mineral oil. Brake fluid is not compatible.
Take a 2" section of a handle bar, bolt it to the back of the headlight. Attach the switch pod to it.
Yes. Air in the system or failed master cylinder seals.
You can take a syringe and force fluid into the slave cylinder. You would see bubbles coming up into the master cylinder.
I don't think that the Fantic's engine has enough Yamaha parts for them to restrict sales in the U.S.
I may be wrong.
The Fantic has been keeping me up at night. But, the Rieju 300I will be a lot cheaper.