It was a cool, but not unpleasant day today in the carport. I pulled the exhaust system and wirebrushed the area where the O2 sensor would go.

I decided that placing the sensor in the center of the collector was more important than the risk of getting the sensor oily. I marked and drilled the hole. I found, as was somewhat expected, baffles inside the collector. As luck would have it, however, my chosen location was not in the center of a baffle, but rather adjacent to one. I used a die grinder to relieve enough of the baffle to ensure that sensor would have access to exhaust from all four cylinders. The die grinder action went a little wild so the hole turned out a little oblong. At least it’s was smaller than the bung.

I suppose it goes without saying that I ran out of oxygen for the torch halfway through the brazing job, and it being Sunday, I should have just gone directly to Home Depot instead of trying closer places first. Even so, I think it came out very well.

I put the exhaust system back on the bike and mounted the LC-1 just below the steering head. That is probably not the greatest place, but I think it was the best place where the fixed cord length on the sensor could reach. I fished the wiring under the tank without removing it, an easy enough task. Solder on connectors, hooked it up, blew up an LED, another trip to AutoZone to get an almost but not entirely unsuitable replacement LED (I could have found a more suitable LED at Radio Shack, but they were closed by then) and finally fired up the ol’ LC-1.

Following the very simple directions for the LC-1, I calibrated it in open air then reinstalled the sensor permanently (I hope).

I hooked up MegaTune to the ECU and started Buzz up. Immediately, AFR was reading just over 12. I didn’t really need the gauge to tell me that the mixture was rich, but it was cool to see an actual figure attached to it.

I already knew that Buzz’s idle pulsewidth was just about at the minimum and it doesn’t look like I can affect idle AFR that way; the pulsewidth just can’t get much shorter. On the other hand, the pressure regulator seems to have drifted up to about 25 PSI. I need to connect the vacuum line to the regulator. That should let fuel pressure run low at high vacuum and higher at low/atmospheric levels. The lower pressure has also affected starting, so I need to tweak cranking pulsewidth as well.

I tried playing with the autotune feature of MegaTune. As expected, it had not room to adjust anything at idle, but I held the throttle at a few fairly low RPMs and was slightly giddy at seeing it automatically adjust the appropriate cells in the VE table. So, there are a couple of 30-something cells surrounded by 50 and 60-somethings.

That lead me to try again to generate a new VE table. It’s very frustrating that the obvious tool to use seems to think that my realworld parameters are erroneous. It want an idle MAP of <=60, but I’m sorry, it’s 72; that’s as low as it gets at idle. If it’s less that 72, Buzz is spinning down from high RPM with the throttle closed, not idling. Furthermore, I can’t seem to make the table generator happy with the horsepower and torque numbers. I entered the published horsepower spec for the stock bike, 50hp at 9000 RPM, but I tried the actual 9000 RPM (no load) MAP in my log of 79. Nope, sorry, the table generator prefers MAP to be =>90 at peak horsepower. I put in 90 like a good little sheep and it makes a table full of big values. So, I guess the table will be mine to generate manually.

Of course, all this MAP trauma is probably because my throttle bodies are too big, which I have suspected for a long time. I might have to build that intake manifold after all.

It’s still fun, in a kinda masochistic way