Tuning with an o2 sensor, advice/tips?

Here it is now after loads of KZR help...

Looks real nicea nicea! Love the blue!

Be very careful! the glass bodied fuel filters have caused more than a few car fires. I'd suggest at your earliest chance to replace it with a plastic body fuel filter.

Bikes have a lot more vibration of frequency and magnitude than cars.

11.8 to 12.5 is good for the idle assuming the bike was fully warmed up (at least 20 minutes). 12 is slightly rich, but you want it set a touch on the rich side. This way the idle speed won't creep up as much as the bike warms up.

I like to break up the throttle into 2 general regions; cruising and accelerating. Cruising is generally 1/16 to about 1/4 throttle. Accelerating is about 1/4 and above. But really, 3/16 to about 3/8 is more like a transitional throttle position.

To check the cruising range, I just hold the throttle steady at 1/16, 1/8, 3/16, and 1/4 while in top gear and wait til the speed tops out. (You get going pretty fast at 1/4.) For cruising you want to be in the high 13 to mid 14 range. With pods, you want to be a little richer like mid 13 to 14 or so at the leanest. This is because the pods are affected by turbulence. Wind gusts and seating position can affect the AFR, so you want to err a little on the rich side. I get best results if it just tops out near 14 on a hot day (85 to 90 deg F). From about 3/16 to 3/8, though, the AFR should transition down into the power range (somewhere around 11.5 or 12).

Then I check 1/2, 3/4, and WOT while accelerating through the gears. For this range, the AFR should drop down into the 11's and will sweep upwards as the RPMs increase. (I really like the analog AFR gauges that Innovate has. That way you don't need to focus on individual numbers and you can see how fast the needle is swinging. If you are using a digital readout, it's harder to get a feel for how fast the AFR is changing). Only pay attention to the AFR after you're past 5000 RPM or so. You really won't go WOT from idle in a fast launch. (Normally you'll have the revs up and will be using the clutch.) Ideally you want the needle to sweep from about 11.5 up to 13 just as you reach redline, or your normal shift point. (I usually do that by sound based on how I normally accelerate when I'm going all out.) Best power is in the 12 to 12.5 range, so you want the AFR to sweep through that range as you accelerate. Because there is such a wide sweep, you have to widen the margin to about 11 to 13.

With manual slide carbs, if you whack the throttle too fast, the AFR will plummet down into the 10's. That's too rich and you'll notice some bogging. You need to roll the throttle to keep above 11.0, ideally (in my opinion).

If you are hitting the 14's at WOT, in my opinion, you are too lean and should go up at least 4 jet numbers on the main.

---

Another thing I should add about mechanical slide carbs, is that some have and adjustable stop for the WOT position. Make sure the slide does not go above the roof of the throttle bore. If it does, that means the last bit of throttle only adds fuel, but no air. This makes the AFR suddenly go rich when the throttle hits the throttle stop. If it's really bad, you will feel the bike actually accelerate if you are at WOT and you start to close the throttle. This also results in an error in main jet selection since it will seem too rich at WOT, but you'll actually be lean for most of the last half of the throttle movement. Just double check the WOT position of the slide, especially if you change needle positions or shims.

hardr0ck68 wrote:

Here it is now after loads of KZR help...

Miracle worker.......:laugh:

MFolks wrote:

Be very careful! the glass bodied fuel filters have caused more than a few car fires. I'd suggest at your earliest chance to replace it with a plastic body fuel filter.

Bikes have a lot more vibration of frequency and magnitude than cars.

Amen.

pictures as promised

plugs:

Number one is on the left and four on the right.
Pic 2

Wide band

The angle is less than perfect, the bung should be slightly higher up the pipe (10 o'clock not its current 8 o'clock position) but such is life.

sensor part 2 If you look closely you can see the relay for my WG coil mod (on the bottom of my battery box)! Can you believe I once thought I was running way rich because my plugs were sooty and fuzzy... the coil mod really helped me out! You can also easily see the gsxr master cylinder I am running. There are no rebuild kits available for my rear master, so I just replaced it. cost me $20.

I talked to a buddy who dyno tunes cars, he says he shoots for around 14 at idle, since there is no load on the motor he believes that is best. Now he tunes primarily fuel injected, water cooled cars...

I honestly don't know if it matters much either way so long as the plugs stay clean at idle.


He told me to shoot for about 12.5 at load as well. I guess I had better order some new jets!

Remember that the Mixture screw will be for Idle, and the pilot get reading would be at 1/8 throttle when the transition circuits are in effect.
Did you do a before Coil mod voltage reading with it running, and a after? If so Difference Please. Thanks.