Author Topic: Dyno testing results - what does this stuff mean? (Read 2991 times)

Dennis · « **on:** June 09, 2006, 12:45:24 AM »

The prior owner of my B12s had some dyno tuning done to smooth power delivery / flat spots after installing a D&D slip on and a jet kit. Looks cool but I don't really understand what I'm looking at. The percieved results are fantastic! The bike runs smooth and strong with no flat spots anywhere in the rev range. But I'm curious about the actual data. Can anyone here help me to understand this? Thanks!

Red01 · « **Reply #1 on:** June 09, 2006, 12:41:15 PM »

What is it you don't understand?

What you have is two dyno runs about 1 1/4 hour apart. The notes don't indicate anything was changed and the lines are so close, little, if anything, could have been done in that time. The changes beteen the lines could be from the changes in temperature (59.66 to 62.43) and atmospheric pressure (30.13 to 30.17).

What I don't understand about it is the A/F chart runs a baseline thru 13... it should be thru 14.7. From this, I see you look to be a little lean at higher rpm, shown as Road Speed on the graph. I think you'd get a little more power if it was leaner on top.

kedeg_97B12 · « **Reply #2 on:** June 09, 2006, 02:58:28 PM »

Paul,
the baseline is the same on my dyno sheet as well. The dyno operator told me that while 14.7 is ideal but not under real world riding conditions so they use that as a benchmark to shoot for. 12.8-13 is a good 'compromise' b/t cruising mpg and overall power.

kedeg_97B12 · « **Reply #3 on:** June 09, 2006, 03:20:56 PM »

If it rides fine with no flatspots or surging, seriously consider leaving it alone.
You can end up chasing your tail trying to eeck out a hp or two.
OR
you can be like the majority of us and obsess, reconfigure by dropping the needle a bit and going up in the mains a bit, test ride, burn your hand making adjustments, then testing some more.

Dennis · « **Reply #4 on:** June 09, 2006, 03:48:37 PM »

Thanks for the replies! I've no interest in tinkering with it really. It runs like a well mapped FI - I'm very happy with the bikes performance. I'm just curious as to what the data means.

Red01 · « **Reply #5 on:** June 09, 2006, 04:14:24 PM »

It means you have a smooth power curve and you're just a hair rich (which is safer than being too lean).

Kind of surprised there's no torque graph, but It ought to be as smooth as the horsepower graph.