Join Date: Jun 2005
Motorcycle: 97 GSX-R750 2008 R6
Re: 1998 gsxr 750 srad , problems......
Doesn't matter if the battery is new or not. It will lose it's charge if it just sits, and cranking the motor just drains it more. If the bike doesn't get ridden, it's not getting recharged. Your battery is probably fine since it's pretty new, just needs charging.
If you're stopped and the fan never comes on, then it will just keep getting hotter and overheat. The radiator needs airflow in order to cool the water. When stopped, or at low speed, it depends on the fan to provide that.
How do you know that running the fan is draining the battery? When the engine is running, the stator is charging the battery. So even if the battery was completely dead, you could push-start the bike and ride off just fine. If something was pulling excess load, you wouldn't know it. You obviously need the fan, so if something is preventing you from using it, then that's your real problem.
If the bike can maintain 170 degrees while cruising on the freeway then the radiator is probably fine. (Hot days it may run 175-180, up to 190 if it's 115 out) But it's a good idea to flush out the cooling system and get fresh coolant/water in there if you've never done so. A radiator is pretty simple, so not much can go wrong. It just has to be able to hold pressure, flow water, and allow air to flow across the cooling fins.
Coolant was low under the left side plastics? That would be the reservoir. I would expect that to be empty if you overheated it, as lots of coolant would have been pushed into there and overflowed. Then some gets sucked back into the radiator as it cools. But for all you know, it may have never been filled. It doesn't matter what cap is on the reservoir. It's not pressurized it just needs to keep the extra water from spilling out. Take off the right side bodywork to access the radiator cap. See if the radiator is full. If it's low, the air compresses as the water gets hot, preventing the system from pressurizing. That allows the coolant to boil and leads to overheating. Another possibility is the radiator cap isn't holding pressure, which would then spit out coolant into the reservoir when it shouldn't. Or you could have a malfunctioning thermostat that is limiting flow through the engine.
So first I would say, make sure the fan can run anytime temps hit 220, and if the system is working properly, it will prevent the temp from climbing farther. If it still gets hotter, verify that the radiator and reservoir are topped off. If that doesn't fix it, I would flush the system. (I would do this anyway for maintenance sake) That will get out any loose debris that may be in there, and give you a fresh coolant/water mix. While you do that, you may want to replace the thermostat. It's cheap, and will eliminate that as the problem. You also may want to test or replace the radiator cap, to make sure the system is holding adequate pressure.