Data Logging for tuning your KZ

Third log is from Feb.18. High temp was 80*f, and all the parameters were the same except that I changed to #125 main jets. Notice from 2:02 to 2:05 where I went full throttle for a couple of seconds an the AFR started out a 12:1 and rose slightly with rpm just like loudhvx has experienced.

The next log is the first of two from Feb 21. High temp was 78*F and I was riding in the middle of the afternoon again. Now with #20 pilots, 4th clip, and #125 mains. I did re-sync the carbs since I was not happy with how the bike had been idling. Most notably the clutch was knocking at idle. I discovered when I did the sync, that #3 carb was way off from the others. I had to remove #3 to install the TPS. The sync took care of my idle problems.

Second of two from Feb 21. This is later in the same ride, and it shows some good part throttle data.

Now the first of three from my ride home from work this afternoon. No changes to jets or clip position from the previous log. I did back the mixture screws out 1/4 turn (richer) from the previous run. The high temp today was 81*F. Notice at 25:16 when I first get on the throttle and the AFR dips down to less than 10:1. This is just off idle when I am giving the bike a little gas to get the clutch out in first gear. It corresponds to a stumble. This condition is consistent and it repeated all the way home.

Second graph from today. Nice full throttle pull where I was passing a car. I shifted down to 4th and gave her the beans for about 3 seconds continuously. I'm rather surprised that the AFR stayed around 14:1 for the whole period. I thought that the move to #125 mains would have gotten me into the under 13:1 range. I seem to be getting similar results from the #122.5 and #125 mains. Seems to point me to a fuel flow restriction somewhere else. Could be my fuel filter or possibly, I need to raise my float level. The floats are currently adjusted to 3mm below the flange via the clear tube method. BTW I did get going fast enough to fold back both mirrors.

Ok, here's the last one from today. I included this one because it demonstrates something interesting. Look at the trend up to 17:07. I'm coasting in gear up to a stoplight. Very light application of throttle to maintain speed. Notice the rpm stays around 3000. AFR is hovering around 10.5:1 and the bike is stumbling. At 17:07 I stop and the rpm drops to about 1200 and AFR is steady at just under 13:1. I need to find a similar situation with the #17.5 pilots in place. It seems to make the transition from idle to roll-on better with the 17.5 pilots, but it immediately gets lean once I get into the throttle a little more with the smaller jets.

I would think that if it was a fuel flow resitriction causing the fuel amount to drop in the bowl, that at the consumption rate of full throttle, the AFR would continually increase (more air) as the level dropped.

Judging from the graph, you only went full throttle from 6000 - 7200 rpm roughly 2.5sec.

Try a larger main jet if you wish, but to me it seems like you would need more WOT data to go on.
Try getting rolling and just shift the bike to 4th. Then crack it WOT, not roll it slowly up. Then just hold it there till red line, or close enough for your likeing, whatever. This will probly give you much more usable data.

testarossa wrote:

Ok, here's the last one from today. I included this one because it demonstrates something interesting. Look at the trend up to 17:07. I'm coasting in gear up to a stoplight. Very light application of throttle to maintain speed. Notice the rpm stays around 3000. AFR is hovering around 10.5:1 and the bike is stumbling. At 17:07 I stop and the rpm drops to about 1200 and AFR is steady at just under 13:1. I need to find a similar situation with the #17.5 pilots in place. It seems to make the transition from idle to roll-on better with the 17.5 pilots, but it immediately gets lean once I get into the throttle a little more with the smaller jets.

I think your 17.5 pilots are fine, as the bike should be fairly lean when cruising for fuel economy. When you begin to use the throttle, forget about jets, its the jet needle and the needle jet, and needle taper that start to make the difference in accelleration mixture.
You will likely have to change the needle.

PS. Before you go any further, maybe you should correctly fine tune your pilot mixtures. X number of turns out is complete crap, they should and will all be different when set to the mixture that provides the most power at idle.
We are talking about 4 little power plants that all have to work together, yet they have minuscule differences that make them require fine tuning.

Good point about the fuel restriction. I'm just stumped that I would need even larger main jets. I'm already 8 sizes above the standard size jets for a VM26 and the change from #122.5 to #125 seems to net no change in AFR. I agree that I need to get a better steady state full throttle pull. It's just difficult around town. I need to get out on a back road to try a sustained full throttle pull. In that little 2.5 second pull I went from 65mph to triple digit speed. Obviously we are nit picking here. The reality is that the bike pulls well enough, but I have a hard time quantifying the results until I get that VR2. I'm really more concerned with the part throttle response than I am with full throttle runs. On thing that this exercise has taught me is just how much time that you spend below 20% throttle when in suburban traffic.

testarossa wrote:

Good point about the fuel restriction. I'm just stumped that I would need even larger main jets. I'm already 8 sizes above the standard size jets for a VM26 and the change from #122.5 to #125 seems to net no change in AFR. I agree that I need to get a better steady state full throttle pull. It's just difficult around town. I need to get out on a back road to try a sustained full throttle pull. In that little 2.5 second pull I went from 65mph to triple digit speed. Obviously we are nit picking here. The reality is that the bike pulls well enough, but I have a hard time quantifying the results until I get that VR2. I'm really more concerned with the part throttle response than I am with full throttle runs. On thing that this exercise has taught me is just how much time that you spend below 20% throttle when in suburban traffic.

Ultimately, a larger main jet "should" correct the mixture at WOT, but the rpm didnt travel very far so its hard to tell if its required.

Yeah, we really do spend alot of time cruising or near cruise, which is where all the fuel economy comes from ahving a leaner setup on the pilots/mix screws.

I want the VR2 as well...

Yes, doing these tests make every road seem shorter, every other driver seems way slower, and any curve seems curvier.

How much time do you have on the o2 sensor?

I think after some initial use, you should re-do the heater calibration and open-air calibration.

I have about 6 hours run time on it total at this point. I did re-do the open air calibration at the point that I added in the TPS. Probably a good idea to re-calibrate every once in a while.