1 Interesting overheat situation, looking for help Thu Feb 09, 2012 4:42 pm
FreebasserSF
Silver member
Hi guys,
Recently my bike has been flashing the overheat light after about 10 or 12 minutes of freeway driving. The odd thing is sometimes it will go off, and sometimes it will flash back on. Sometimes it will be on and then I go up a hill and halfway through it goes off. Sometimes when I pull in the clutch quickly it goes off as well and if I'm in first gear and linger in the sweet spot where the transmission is about to take over and accelerate the bike, the light will also go off. I've heard that on a downhill run sometimes the light will go off because water goes through the thermostat if it's not functioning correctly, but this isn't the case.
I just tested my temperature sensor with a multi-meter in hot water like Crazy Frog did in "oh dear and now temperature issues". This is the chart in fahrenheit if anyone is interested.
I checked the temperature conversions and it seems just about the same, so this means my temp sensor is working. This makes sense because I assume it was working before as the temp light never came on. What doesn't make sense is that the temp gauge which is connected directly to the water pump drain plug is working just fine. It gets up to normal and stays there as it should. I haven't tested the gauge with hot water yet so we can put that on the list of things to check, but it doesn't seem like it would fail overnight. I have the right amount of coolant in the bike, I tested the thermostat in hot water and it opens at 85 degrees celsius where it should. The overflow tank rises when the bike gets hot. The oil is at the right level and I opened the oil drain plug to let some out and didn't notice a sheen in it (I assume since oil floats on water, the water would be at the bottom of the oil sump.) I've gone through all the connections on my bike and sprayed with Deoxit D series and gold series, and have scraped oxidation off and sprayed all the grounds I know about. I have burped the radiator cap many times to try and eliminate air bubbles. The radiator fins are in pretty good shape. The fan is working, but it usually spins slowly and kind of in spurts until after about 8 to 10 minutes then comes on full blast and creates quite a cold draft (and yes its blowing the right way). I haven't tested the RPMs on it and don't know how, but I assume it's working.
So given all this information, and assuming the temperature gauge works (for now), I wondered what you guys think about this: The temperature gauge lead is connected directly to the water pump which is before the coolant goes into the engine to cool it, and says the temperature is normal, the temperature sensor is on the pipe coming directly out of the engine, which works as it should and is saying the temperature is too high. I have deduced a list of possibilities. Maybe the water pump is partially blocked and doesn't get water through to the engine in the right amount and so as a result the water on the temp sensor is hotter. Maybe the water pump isn't working at all, but I would think this isn't the case since water seems to be circulating. Maybe it's a plain old error in the temperature sensor relay. Maybe the coolant temperature light is not working (although that doesn't make sense because it comes on after a certain amount of time pretty consistently). If something was clogged in the engine part of the cooling system I think this could cause it but I don't know how I would snake something in there to check.
I have probably given you everything I know and exhausted any readers who have made it this far so I will stop. I am just hoping this causes a lightbulb for someone and could offer some tips about what to do next, and if this involves anything like taking apart the water pump, being so kind as to include any gaskets, washers, or other parts you're supposed to replace each time. I will be happy to take pictures of anything anyone asks me too (on the bike that is ) if anyone thinks that will help.
Recently my bike has been flashing the overheat light after about 10 or 12 minutes of freeway driving. The odd thing is sometimes it will go off, and sometimes it will flash back on. Sometimes it will be on and then I go up a hill and halfway through it goes off. Sometimes when I pull in the clutch quickly it goes off as well and if I'm in first gear and linger in the sweet spot where the transmission is about to take over and accelerate the bike, the light will also go off. I've heard that on a downhill run sometimes the light will go off because water goes through the thermostat if it's not functioning correctly, but this isn't the case.
I just tested my temperature sensor with a multi-meter in hot water like Crazy Frog did in "oh dear and now temperature issues". This is the chart in fahrenheit if anyone is interested.
I checked the temperature conversions and it seems just about the same, so this means my temp sensor is working. This makes sense because I assume it was working before as the temp light never came on. What doesn't make sense is that the temp gauge which is connected directly to the water pump drain plug is working just fine. It gets up to normal and stays there as it should. I haven't tested the gauge with hot water yet so we can put that on the list of things to check, but it doesn't seem like it would fail overnight. I have the right amount of coolant in the bike, I tested the thermostat in hot water and it opens at 85 degrees celsius where it should. The overflow tank rises when the bike gets hot. The oil is at the right level and I opened the oil drain plug to let some out and didn't notice a sheen in it (I assume since oil floats on water, the water would be at the bottom of the oil sump.) I've gone through all the connections on my bike and sprayed with Deoxit D series and gold series, and have scraped oxidation off and sprayed all the grounds I know about. I have burped the radiator cap many times to try and eliminate air bubbles. The radiator fins are in pretty good shape. The fan is working, but it usually spins slowly and kind of in spurts until after about 8 to 10 minutes then comes on full blast and creates quite a cold draft (and yes its blowing the right way). I haven't tested the RPMs on it and don't know how, but I assume it's working.
So given all this information, and assuming the temperature gauge works (for now), I wondered what you guys think about this: The temperature gauge lead is connected directly to the water pump which is before the coolant goes into the engine to cool it, and says the temperature is normal, the temperature sensor is on the pipe coming directly out of the engine, which works as it should and is saying the temperature is too high. I have deduced a list of possibilities. Maybe the water pump is partially blocked and doesn't get water through to the engine in the right amount and so as a result the water on the temp sensor is hotter. Maybe the water pump isn't working at all, but I would think this isn't the case since water seems to be circulating. Maybe it's a plain old error in the temperature sensor relay. Maybe the coolant temperature light is not working (although that doesn't make sense because it comes on after a certain amount of time pretty consistently). If something was clogged in the engine part of the cooling system I think this could cause it but I don't know how I would snake something in there to check.
I have probably given you everything I know and exhausted any readers who have made it this far so I will stop. I am just hoping this causes a lightbulb for someone and could offer some tips about what to do next, and if this involves anything like taking apart the water pump, being so kind as to include any gaskets, washers, or other parts you're supposed to replace each time. I will be happy to take pictures of anything anyone asks me too (on the bike that is ) if anyone thinks that will help.