1986 VFR750F. Previous owner filled system with 100% WATER--No Antifreeze. Pulled water pump and impeller blades rusty. Rusty water in bottom of impeller cavity. What water there WAS in the Radiator is Rust colored and just "nasty". NO liquid in overflow tank. Signs of rust and calcium buildup at radiator cap. Radiator removed and gently flushed with garden hose. How should I proceed to "fix" this situation? Take radiator to auto shop and have them flush it out? Do I need to replace water pump or attempt to clean it up / out? After radiator flushed Should I fill with Vinegar and try running bike and cleaning out hoses etc that way or what? Afraid if I flush with Vinegar the worry is this will loosen rust and debris and clog the passages in the radiator and motor passages etc. I am VERY OPEN to suggestions. Thank you in advance for the courtesy of your input. Rick
I had something similar on my ST1100 which had been parked up for 10 years and had suffered a coolant leak before that. Lots of scaly corrosion, and the thermostat was dissolving; I purchased some radiator cleaner at an auto parts store that was specifically OK for aluminium. You add this to the cooling system and run the engine for a minimum amount of time (30 mins IIRC), then drain and flush with water a few times. Touch wood I've had no issues in the 6 months since I did that. When you drain the coolant on the VFR you should make sure you get to the drain bungs under the front head as well. That is a low point where gunk will accumulate.
The 85 VF1000F project I'm working on is like this. I'm getting the rads professionally flushed and cleaned. Imoeller was good thankfully.