Hi everyone,
I just registered to share my story - I've been on a bit of an odyssey the last two days trying to figure out why my K100 wouldn't start anymore after standing for a bit in some heavy rain.
I started by checking for fuel and spark (all plugs were wet so no issues there). I tried unhooking the water temp sensor, which led to some backfiring and actually let me start the bike for a little while after plugging it back in - there was a lot of smoke and it didn't want to run well at all.
I measured the other sensors, but everything checked out. At this point, I had a look at the oil sight glass and noticed the oil had water in it - it looked like a milkshake! Normally, this would point towards a bad water pump seal (în the case of K bikes) or a bad headgasket (on any other engine) - but the coolant was squeaky clean and the headgasket was good before I let it stand, so I figured it wouldn't have dissolved magically. And I just knew it had to be connected to the rain, because everything was running great when I last parked it.
The oil also didn't smell/taste of coolant at all, so I thought it had somehow caught some rain through some hole I didn't know about. I followed some other bad leads before I had a look in the tank - of course it was a mess in there, a completely opaque mixture of gas and water, sorta looked like lemon juice. I siphoned the ~3 gallons of junk off - here's the bottles with the most water in the bottom:
That's probably almost a liter of water that was in the tank - no wonder it was barely running!
After drying and refilling the tank, the bike already ran a lot better but still wouldn't idle - there was probably some water left in the fuel filter; the oil is also slightly cloudy again. Waiting for about half an hour magically cleared that up and now everything is back to normal (except for the oil, which looks nasty and I'm all out...)
I guess the water in the fuel must have made its way past the piston rings (not like these bikes are known for a hermetic seal there...) and into the oil. I've never heard of this happening before but it makes sense when I think about it. In any case, I'm always gonna cover or garage the bike from now on!
