Sounds like a show at Marineland, but in fact I discovered my crusty KLR was weeping coolant and thus needed some hot wrench-on-engine lovin'.
For excellent step-by-step instructions, click here. Big thanks to MarkNet for his great KLR info. It's a pretty straightforward job; the biggest pain is pulling the old seals if you don't happen to have exactly the right length of threaded rod right where you thought you left it from the last job.
Kawasaki part numbers and prices from Ottawa GoodTime Centre are as follows:
Mechanical Seal, 49063-1056, $25.46
6mm O-ring, 670B1506, $1.76
Oil Seal (SC10227), 92049-1157, $8.42
Total cost with OEM shipping charge ($3) was $43.66. Also factor in the cost of an oil change and about 4 hours of wrenching if you're not perfectly set up to work efficiently. Like working past dark in the driveway. At least the mosquitos haven't come out in force, although I did see one.
Turns out the oil seal was pretty worn. There was corrosion inside the weeping chamber. Although the repair was a pain (drain the oil, drain the coolant, wipe up spills of both, forget there's still oil trapped under the oil filter and spill more oil, get interrupted by dinner, etc.) I feel a lot better knowing my water pump's good for the rest of the time I'll own this bike.
Props to my neighbour Ken who graciously held my trouble light and entertained me with stories, then buzzed off a water pump gasket on his nifty laser cutter. Took about 5 seconds to cut, not counting the hour or so I spent a couple winters ago scanning the pump cover and tracing it in Illustrator so it could be laser cut. I have a few gaskets on file now, any of which can be made on the laser using almost any material.
By tomorrow the gasket sealer will have set and I'll fill up the oil and coolant, take a test ride, and do an oil change to remove any debris that got in. Ready for the trails!