I had a bit of a quiet monday morning, it was a beautiful autumn day, decided to take the 907 for its first dyno run
Still remembering the sale pitch from Vince, the Ducati dealer in Ringwood when I bought the bike back in '92...fit the staintune pipes + header, together with the upgraded chip, that should give you an extra 8 something or other (dont remember Kw or Hp) so I had a figure in my head of at least 85Hp at the rear wheel
I recently changed the chip, removed the FIM chip and installed the FBF stage one unit, the ferracci chip is very smooth down low in comparison to the FIM unit, as this had a rough behaviour between 2.5 and 3k rpm, but I suspect the FIM chip had greater potential for Hp once you've gone past the 4k mark, and the motor definitely ran richer
The 907 is a great bike, and to me a good smooth torque delivery is most important...leave the Kw's for the young ones
So I rode the bike to Dynobike in Moorabbin and Dave put the bike through its paces right up past redline to 9.5k rpm




and here is the result...a bit disappointing with the Hp...only 72.07 less than their advertized figure approx 53Kw
but when you look at the torque figure, I think thats quiet impressive (not a high figure but good none the less)...90% reached at only a bit passed 3k to reach a peak of 51.52 at 7k rpm



the other thing I was interested in and someone more qualified can tell me, is the fuel/air ratio
if you look a the next graph it seems to be all over the place and run lean under hard accelleration (13 should be normal) Dave said that the cruising speed reading is more important



so he took the bike through the revs at cruising speed (slow accelleration) and the reading between 2k and 7k was constant on approx 13.7 see next pic...a bit lean but should I be concerned or thats not too bad



any replys would be appreciated

an AFR of 13.7 at cruise for that era of FI is pretty good It is actually slightly on the rich side of things.

AFR is the ration of air to fuel
air is the larger number
fuel is the lower
So a lower(13:1) means less air per volume of fuel

making the mixture richer not leaner

a number of 17:1 would be a lean mixture and not something you want to see at cruise, it would melt your pistons eventually.

thanks higgy, so thats not too bad for a vintage
the other thing I didnt mention was the humidity, during the test it was fairly dry 34%...does anyone know how much difference or improvement in a combustion engine when there is 90 or 100% humidity,
I know cars run better when it rains, but I'm not sure by how much

Humidity has little noticable effect on the Power of combustion.
The cooling systems generally transfer heat much better when the humidity is higher which is what you notice in the seat of your pants. Also the air is somewhat denser so you improve volumetric efficiencys.
it comes down to fewer losses than actual gains.
Of course the seat of your pants could care less what the actual reason is

Thanks for sharin!


IRL, 907 seems to actually have 74-75 Hp at rear wheel when in good shape & w free breathing. So yours is within the error margin, different Dynos, air conditions, tyres etc.

If it was a WOT run I think the A/F is too lean , esp 6-9k RPM.
Closer to 12.5 there would give more power.
But as you say cruising area more important.

What A/F did you have around 3700-4700 RPM cruisin?

I dont know what a WAT run is but on the chart it says BASE run
during the cruising test the reading seemed to be a constant 13.7 (between 2 and 7k) and he didnt go past 7k
...I wonder what happens if I fit the chip from the 851 in the 907

WOT is wide open throttle

I am far from an expert on the subject, but from what I have read, Dyno numbers can be quite misleading. There can be considerable variation from machine to machine and from run to run with no changes made to the bike. To get a proper Dyno reading, my understanding is that you need to do about 5 runs minimum to form a baseline for your bike. You can gain a few horspower often just by a second (or third) run.

When I have had a bike Dyno tested, the printout will usually tell me how many runs have been made. I note on your printout that it says "Base Run" which may indicate only one run. If that was the case, what it shows to me is that your bike is performing within specs. I would be more interested on a single run in the air/fuel ratio than the horsepower (which I would consider an unreliable figure with only one run).

Having said the above, I am a BIG believer in the Dyno as a tuning instrument when used properly. I am not aware of anything that will give you as true a picture of your performance as a Dyno test.

On the subject of dyno runs. It is what I currently do to pay the bills so I think I know a little about it.

First a baseline run generally yes consist of a minimum of 5 runs. The idea being to produce repeatable numbers. Baseline would also be done before any modifications are done. Official results for a baseline run would be complete when ALL the data collected is within 2%. 2% for the corrected results which has nothing much to do with published results. Has everything to do with the standard required by the "governing body" you are presenting the data too. This standard can vary widely. In our case we have a constantly evolving manual detailing the methods we must use even to garner approval to submit our test plan...thousands of pages of documentation. not a lot of wiggle room In my case I have 3 masters degree type engineers just to keep up with the standards we must adhere to. Not to mention the others that do the development end of things, the real experts!!! My job,lucky me is to figure out how to do it. WTF was I thinking when I took this J.O.B.

Once you have your baseline results and they are accepted by the "governing Body" you are dealing with,
you then submit your test plan wait for approval and then do what ever mods you are researching and do more runs on the dyno to get the same 2% range of data. In my end of the dyno world this involves hundreds and even thousands of hours of data on NIST traceable equipment. We are talking literally millions of dollars per annum just to present the data to certify our equipment as capable of doing the data collection
If we do all this correctly and garner certification we may then and only then present our data to the world at large.

One last comment on dynos, they are far from the best way to do any testing, to do that requires real world results and dyno testing is most definitely not the real world.
and has never won a race, if that is the sort of thing that matters to you

On p7 you will have to make a choice cuz you can't do it all. You have one of three choices. do you want to optimize the low,the middle or the high range or you could put a Weber on it

You`re hallucinating again, higgy......
What you do is put a MyECU on it!

Claude,

Is that my recovered seat on you bike???? Looks good.

I have just installed an FBF stage 1 on my bike to compliment my Termi's and free-er breathing air filter too, perhaps I should give mine a run on the dyno next time she's in Melbourne.

Cheers