This story is about air filters - really.
There was some recent traffic about air filters on the OSKRG email list - about where to get replacements inexpensively. My local TrueValue hardware store had the best deal - $5.99 for a Fram CA77. They had to order it, and it took a week to arrive. The one on my bike was old, and a little dirty, but not too bad. What the heck, for $5.99, I'll get a new one.
My "new" 1962 XLCH was missing the generator and regulator, as the former owner drove it at Summit Point racetrack on weekends, and didn't need no stinking lights. After finding a generator and regulator, and rebuilding both, I was ready to install them. I removed the gen block-off plate, and to my surprise, found out the former owner had also removed the idler gear. I found an idler gear on eBay. I asked the seller if he had the fiber washer that went on the idler. He said he had had more than 50 Sportsters, and always left the fiber washer out. I found some elsewhere on eBay.
Installing the idler gear meant removing the cam cover, which meant loosening all the tappets, and also meant removing the magneto, which meant removing the carburator. I put the idler gear and fiber washer in, tightened the cam cover, put the magneto back in, and went to rotate the engine to the timing mark. But it would not rotate. At all. I pulled the cam cover back off, removed the fiber washer, and put it back together. It rotated just fine. I put everything else back together just as I had taken it apart. While I was at it, I threw in that new air filter. The bike fired up, and I drove it around a little, before giving it a good bath with the garden hose - especially the area behind the magneto where much grime had built up over the years.
The next day, I took it out for a good long ride. It ran fine at low speed, and accelerated fine, but ran quite roughly at any steady speed above 30 mph. Never did that before. What's going on? It seemed like an ignition problem, and I figured I had gotten some of water inside the mag, and it should dry up by the next day. So yesterday I took a longer ride, but the problem was still there, and it wasn't going away by itself.
Yesterday evening, after putting in my shiny new 4031 headlight, and redoing the wiring (much was missing), I wanted to take it for a ride in the dark to see how the headlight performed. I drove up and down my street (5 miles end to end) waiting for it to get dark. But it wasn't getting dark fast enough, and wearing just shorts and a t-shirt, it was getting cold. Three deer jumped out in the road in front of me, but not close enough to make me hit the brakes. And that's when I saw the bear. A big ole black bear came out of the woods, ambled across the road in front of me, and headed off into the woods on the other side. Remember that old advertising slogan: "You meet the nicest creatures on an XLCH". I figured I'd just go home and wait for it to get really dark. I cracked open a cold beer and waited. Still not dark yet. So I cracked open another one. By the time I finished that, it was pretty dark, but I figured I'd better not push my luck too far -- Mr. or Mrs. Ursus might be out there in the dark just waiting for me.
Today - time for action. I pulled the plugs - dry black deposits - too much gas. My first thought was to adjust the carburator, but I hadn't messed with the carburator, so I didn't. It had to be something I had recently messed with. So the next thing was to check the points, even though I hadn't actually messed with them. Dead on .015. Timing - right on. It sure didn't seem like anything to do with the tappet adjustment - they made a little noise when cold, but quieted down after the bike had warmed up. What could it be? Points - timing - tappets - I hadn't messed with anything else.
Oh yes I had! I had put in the new air filter. I was about to put the old one back in to prove my point - but then remembered - dry black plugs - too much gas. The old one must have been pretty crudded up and restricting the air flow, and required a richer setting. I cranked the carb's low-speed needle in (lean) 1/2 turn, and it ran much smoother in the garage. Took it out on the road, and problem solved!
So - replace that ancient air filter - it's probably a lot more crudded up than you think.
Dave