Two questions...

How hot the voltage regulator can be between normal parameters?
And, why Im having a few oil inside the airbox?

 

V regulator can get quite hot, you have to remember the total current use of your bike is passing through the voltage regulator.

poor connections can also add to the heat at connector.

the carbs do pull air from the crank case through the breather tube and can pick up some oil
is your air filter clean?

oil in the air box comes from the breather tube on motor .
causes can be overfilled/ high oil level. fuel leaking from carbs causing high oil level or you just put too much oil in the motor.

then there is mechanical problems, cylinder blow back could be bad rings or a hole in the piston allowing the compressed air to force into the lower crankcase

do a compression test

 

Thanks...I'll tty to do the test....paper air filter had a little oil too in the bottom. And one more question for the road. Since I check the carbs and are ok but I still have my spark plugs with a thin layer of carbon is that possible tham I'm riding the bike under the rpms needed to clean the sparks? If it is so at what rpms should I ride the bike? My other bikes were choppers or customs with 2 V cilinders, a lot of torque ftom the bottom and not too many rpms. For me this is kind of a custom with a racing heart...and Im not sure Im riding it like I should hence all the problems Im having...

 

the motor is a low compression high rpm motor. It comes to life at about 5k rpm. you can red line it in any gear and the motor is not supposed to care not that I recomend it

 

The plugs should self-clean at idle once the engine reaches normal operating temperature.