I had an odd thing happen a couple weeks ago. I jumped on my 1953 BMW R51/3 to go visit a guest in town over at a friend's house. I fired it up — first kick start, just like usual — and rode down the hill. But as I tried to use more throttle going up the incline towards the back exit from my home, I found that the engine seemed to be missing about about 3/8's throttle. I turned around and rode back home, struggling up the steep road to my house.

I had no time to look at it later that week. I put it on the lift and ignored it for a few days. This often seems to be the best technique for fixing things. Having no real brainstorms, I took off the front cover and verified that there was no arcing across the points (could be a sign of a dying condensor), no sparks jumping the safety gap on the magneto (bad plugs, caps or high tension leads), and that the centrigual advance weights seemed to be moving appropriately.

I also thought it might be a fuel starvation issue, so I checked the screen in the petcock bowl and checked the fuel flow rate. The screen was clean and I seemed to be getting at least 1/3 liter of gas/minute out the fuel lines.

So, I left the bike up on the lift for a few more days. It seemed I was going to have to go in deeper to solve this mystery. Although I didn't have a good reason for thinking so, it seemed that it was more like fuel than ignition. I leaned over the left carb, thinking about how annoying it was going to be to take it apart and clean it. Maybe there was some water in them.

As I was leaning over, my eye momentarily wandered to the air cleaner. There it rested — there was something odd about it. I gave it more attention and realized that the choke lever, which I never touch because the bike doesn't need it and BMW's manual recommends only using it when the temperature is below freezing, was completely closed.

About 4 weeks ago I had my annual Tech Day here. I can't say for sure, but it may be that someone closed the slide then. I'm not sure I've ridden the bike since then. I love having the event and getting people interested in old bikes. Perhaps someone didn't know what that lever did, although it's definitely a generational thing: I've never owned a car that had a choke, but when I related this to my mom, she instantly said that those symptoms matched a closed choke.

Anyway, I quickly checked the choke on the R60/2, just to make sure.