Gaahohaaalie! (Like Gomer Pyle). You ain't gonna believe it, you just ain't gonna believe it! I would have told you were wrong if I hadn't seen it myself.
All you stock boys, we may have an opportunity here. But first...
The white wire is evidently not the optimal power source because when I turn on the HI BEAM the AFR gauge loses power. Easy enough to resolve because no wires were cut. Just have to break out the multimeter again.
I have not started doing my official testing yet, but I rode it with the gauge up and running. What an eye opener.
Choke idle is pig rich, but it's supposed to be that way so whatever. It's like 8.0 or richer ... my wideband sensor doesn't go richer than that.
Warm idle is a healthy rich. About 11.2. Both choke idle and regular idle are richer than what I've tuned the Scamp to. Nothing negative about that. Just how it is, from the factory. But a good learning lesson for me ... maybe I need to be a skosh richer on my Scamp.
Cruising, moreso at higher rpm, it is stratoshpherically lean. Near the lean limit of the gauge. Running 18 - 20 AFR at 45 mph and higher. Don't worry, I will have better defined numbers and maybe even a plot later.
But here's they eye opener. Bear in mind, my bike is new so everything is fresh. And with enough level ground the speedometer will get very close to 80 mph. So it is running right. But at WOT it is RICHER than optimal! Wow! I would not have believed this!
I wasn't on my testing grounds and so I could only pull 65 mph in 4th to hit max rpm at full throttle, but at WOT it starts out at like 9.0 AFR and at max rpm it hits only about 10.5 AFR!
So yeah, rich. Richer than 12.5 AFR. That means I'm gonna have to do some math (I have a spreadsheet already) and downsize the main jet. The opportunity is that 12.5 AFR will use less fuel, and will make more power! Will more power at 12.5 be noticeable? Dunno. That's what my testing will determine.
Also, what I believe is that the jet kits on carbjetkit help not with power, but smooths out power and improves driveability due to shimming the jet needle up. Which richens up the cruise AFR which woukd make it run more smooth. Because under certain lean conditions, it stumbles like it is running out of gas. I may shim the jet needle too later ... but before that I will tune the WOT AFR and see how that affects the performance.
Hope you guys and gals find this interesting, more to come!
2016 Honda Rebel 250 - The "Piglet."
AFR sensor equipped and downsized to a 0.105" main jet.
The only changes so far.
Bought on 6/29/19 with 44 miles.