breyfogle
New member
About two weeks ago, or so, I'm riding home after work. Temperature is in the low 80's (nice for January, even in LA) when I got stuck in stop & creep traffic with no way out. No big deal I think, until I feel something HOT on my right leg. Looking down, I see that my K75S (1988 / 126K miles) is beginning to do a fair imitation of a steam engine. Only then did I notice that the Hot idiot light was on (never seen it on before). The fan wasn't working. My only choice was to get moving and hope for the best. Lane spliting is quasi-legal in California but its not something I do often on surface streets but it worked, at least in the sense that the Hot light went out almost immediately. The motor did continue to pi** coolant the rest of the way home.
Once home, it did not take long to figure out that the radiator fan would not turn. Frozen solid. The next day, I removed the fan assembly and opened up the motor housing. I know that these fans have a history of failure where either the bearings seize or the motor brushes melt. In my case both plastic brush holders either broke or melted, which jammed the metallic brushes themselves against the motor commutator, rendering the motor both electrically useless and jammed.
I ordered and installed a new fan assembly, drained and refilled the cooling system and the engine oil. The bike started easily and sounds normal when idling in the garage. The bodywork is still off so I don't know yet how it will run on the road. Is there anything else I should be looking for or checking ?
I did have one suprise removing the radiator. Drained the coolant, loosened all the hoses, unplugged the electrical connection and took off the radiator. While turning it over to get the last remaining coolant out, I heard a rattling sound, like a ball bearing rolling around inside. That's odd, a radiator should not do that, but every time the radiator tilted, there was definitely a ball bearing type noise. With a little shaking, out fell the 7mm hexhead from an OEM hose clamp! No screw threads, just the head! This particular radiator has not been off the bike in probably 10 years, at least. Would any of the assembled K-bike guru's like to hazzard a guess as to just how part of a hose clamp could end up inside the radiator tank ?
Long story short: check your rad fans, even the youngest K75's are almost 15 years old.
Once home, it did not take long to figure out that the radiator fan would not turn. Frozen solid. The next day, I removed the fan assembly and opened up the motor housing. I know that these fans have a history of failure where either the bearings seize or the motor brushes melt. In my case both plastic brush holders either broke or melted, which jammed the metallic brushes themselves against the motor commutator, rendering the motor both electrically useless and jammed.
I ordered and installed a new fan assembly, drained and refilled the cooling system and the engine oil. The bike started easily and sounds normal when idling in the garage. The bodywork is still off so I don't know yet how it will run on the road. Is there anything else I should be looking for or checking ?
I did have one suprise removing the radiator. Drained the coolant, loosened all the hoses, unplugged the electrical connection and took off the radiator. While turning it over to get the last remaining coolant out, I heard a rattling sound, like a ball bearing rolling around inside. That's odd, a radiator should not do that, but every time the radiator tilted, there was definitely a ball bearing type noise. With a little shaking, out fell the 7mm hexhead from an OEM hose clamp! No screw threads, just the head! This particular radiator has not been off the bike in probably 10 years, at least. Would any of the assembled K-bike guru's like to hazzard a guess as to just how part of a hose clamp could end up inside the radiator tank ?
Long story short: check your rad fans, even the youngest K75's are almost 15 years old.
