Motorcycle Repair: Motercycle, honda v65, vacuum hoses

Question
My Honda V65 is overheating and my prestone boils out the over flow. I have cheeked the water pump,sensor,thermostat and fan. And there are no issues with them. It spent 4 weeks at the Honda Dealer ship and no change. What do you think it is?

Answer
Jeff,
did they try a different radiator cap?
If it sucks air in the system, it will have problems.
The fan isn't slipping is it? Can happen.
Is the bike running lean for some reason?
Check the plugs, they should be tan colored.
Check for any loose vacuum hoses or
air leaks on intake or exhaust system.
Is the radiator plugged? Hoses collapsing?
Possible the head gasket is blown,
does the oil look free of any coolant contamination?
Does it blow any whitish colored exhaust?