It started just as I was leaving Big Bend to head back to Dallas in December — I started the engine and you could smell antifreeze from a slow drip coming out of the weep hole under the engine and dripping on the hot exhaust pipe.
I went back in the room and did a little research on f650.com and found out it’s an indicator of a failing water pump. Unsure I would make it back to Dallas I checked in with Paul Glaves and he told me to stop by on my way north to Alpine. The dripping had stopped and he said I had plenty of antifreeze so I should be fine to get back home. I ran into ice and snow on the way home, but the water pump did fine.
Due to the lovely winter in Dallas I wasn’t doing a whole lot of riding, but when I’d start the motorcycle to run it the drip would start again. Since I have solo trips planned I want it changed before them. I did more research and it was suggested that you should be able to insert a probe into the weep hole to about 38mm if everything is okay and hit the metal impeller shaft. If things are deteriorating you will hit rubber at about 30mm. I hit rubber at 29mm.
I talked again with Steve Johnson of f650.com — he thought I could make it down to the tech day in San Antonio, but I have so many other things to do that I wanted the water pump changed before going.
I asked Joel Watson and Randy Simoneau if they would help me since I had never gone into the engine before – whew, what a job.
The oil and coolant both have to be drained before. The “water pump cover” only exposed the impeller and the left engine cover has to be removed. The oil return line to the top oil reservoir is a hard metal pipe that will not allow the cover to be removed. BMW mechanics may know how to get to the screw holding the top bracket for this pipe, but we couldn’t see any way to get to it and ended up taking a hack saw and cutting the pipe.
I was quickly proved to be a needed repair when the impeller and shaft were finally removed. The were deep grooves worn into the shaft from the deteriorating seals.
In the meantime Joel had taken the new parts from me and put the new seals on a tool on the work table. When Randy and I went to install the new seals one of them was missing in action. I mean totally missing. Over an hour of searching — Randy and I full time and Joel and Ralph Swartz pitching in part time. We looked behind everything, under everything, crawled all over the garage floor. We figured a round, hard rubber seal could bounce and roll about anywhere. We even looked outside since the garage door had been open. It appeared the thing had grown legs and gone for a walk.
For the fourth or fifth time I decided to check the work table. I lifted up a magnetized bowl for holding screws to look under it and lo and behold the missing seal was attached to the bottom of the bowl. The seals have a metal spring ring embedded in them that was enough to hold to the magnet. It’s actually kind of funny in retrospect. It was NOT funny at the time.
Got the new impeller, shaft and seals in. Replaced the engine cover. Spliced the cut oil return pipe with a section of hose. Reassembled all the plastic and I was good to. It only took five hours. Okay, four hours if you don’t count the hour long hunt for a sneaky seal.
Important point to this repair. Steve Johnson said the reason the seal goes out around 40k is that the BMW coolant breaks down and become gritty and wears out the seals. This was accidentally confirmed for me when I was talking to another F650GS owner and she mentioned her husband changed her coolant and it was almost like there was sand in it. Steve Johnson says to use only Honda coolant in the blue bottle and with that coolant the new seals should last 80k. I think I can maybe face doing this project again at 120,000k…
A big thank you to Joel and Randy — they were a blast to work and spend the day with. And might I add not one swear word the entire day. Joel at one point called my motorcycle a pig to which I took great offense. His response “They’re all pigs — okay, yours is a piglet.” I can live with that.
