I've been listening for almost a year to many of y'all dudes talking about the half spacer mod. "Blah blah half spacer blah blah blah half spacer...", etc. I heard it so much that I started to dream it (plus the mixture screw behind the brass plug). I finally started working on it, and see the picture above for what happened. Surprised? I think not. I read that the screws are a common complaint. Here are some of the not-so-comical things that happened which reminded me of my younger years, when things like this happened nearly every week.
1. Stripped one carb cover screw with a screwdriver (Stanley that was a hair smaller and pointier than the required Phillips #2 from Craftsman).
2. Stripped two other screws with what seemed like a better Phillips head attached to a ratchet.
3. After removing one screw properly with a #2 Craftsman Phillips bought the next day, I got the other 3 off using needle Vise Grips. That was after I had broken a brand-new screw extractor (tap) on the first try.
4. It then went well until somehow the needle spring got hung up on the tiny washer as I was trying to screw the needle cover plate back on.
5. Unjamming that caused me to lose the tiny washer on the garage floor for 40 minutes. I had bent the plate, so hammering that back flat again removed the infamous dimple.
6. It started to go well again as I put the 4 new allen-head carb cover screws back on. Then I noticed I had forgotten to put the slide spring back in. Whee.
7. I nearly screwed up the plastic screen on top of the petcork due to trying to put it in *after* I bolted the tank back down.
My backing out the mixture screw 2.5 turns was uneventful, thankfully. I also replaced my petcork vacuum line with fresh fuel line, and I tightened up the rubber ducting on both sides of the carb. It seemed plenty loose.
After all this trial and error, I'm happy with the result. The bike seems smoother with some more guts, and I feel more confident at highway speeds. I hope the MPG hasn't gone into the gutter now. The backfiring is now more of a rumble, and that annoying bucking when you start to lug the engine isn't as pronounced. I remember having a guy sort of laugh at me once as I did a buck-fest in a parking lot once in 1st gear.
My advice to those doing a spacer mod for the first time is to go slow and make sure you have a high-quality #2 Phillips at the least. Hammer it into place before trying to turn any screws. If that won't work, drill into the top of the screws some and use needle vise grips.