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Dyno Interpretaion
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Author:  TheClaw [ Sun Feb 15, 2015 12:20 pm ]
Post subject:  Dyno Interpretaion
I posted this image in the picture thread following the arrival of my bike but thought I'd get your collective thoughts specifically on the dyno run.

Attached is the image from MCC's dyno. It's our baseline run. I would have thought the bike would make more power and the torque curve looks a bit weird. What do you think?

Image
Author:  Palmer [ Tue Feb 17, 2015 2:44 pm ]
Post subject:  Re: Dyno Interpretaion
Jeff,

Yah, looking at the dyno graph looks a little weak. The air/fuel ration doesn't look ideal. The power appears to be dropping off early but without knowing much about the engine build it's hard to say. Couple of things I would do if it was mine would be:
1. Check compression
2. Do a leak down check
3. Check the timing with a light
4. Adjust jetting to get 12.5 A/F through most of the pull
5. Check the cam open and close with degree wheel
These would at least tell you what you have without having to tear it down. Once you get more details it may become a little more clear as to what the motor needs. Hope these suggestions help.

Palmer
Author:  sports [ Tue Feb 17, 2015 11:54 pm ]
Post subject:  Re: Dyno Interpretaion
The best thing ever invented is the air/fuel ratio gauge. I have fitted these to all the race bikes. Long gone are the days of trying to read a plug that has done the warm down lap after a race, idled down pit lane then across the paddock before removal. It saves endless time and, lets face it, -- guess work.
The rider can see exactly what is happening, -- precisely when it is happening. The Dyno is a great tool for many things, but the air/fuel gauge illustrates data directly relevant to air temp and pressure, throttle position, revs etc on the day. Be it on the road, at the track or during the race, and not in a dyno room with maybe significantly different conditions some weeks previous.

I am sure anyone reading this who has fitted one to their own bike will agree.
Author:  marcotoys [ Wed Feb 18, 2015 9:00 am ]
Post subject:  Re: Dyno Interpretaion
Thanks for your input Palmer and Glynn.

Glynn, would you please post some photos illustrating how to install an air/fuel ratio gauge on a F1 ?

How should I modify my exhaust system to install the gauge (one for each cylinder/carb or one for both ?)

Would you please tell us also your recommendations about the brand and model I should buy for my F1 ? (During last winter, I have boosted my engine and this coming Spring I would like to get the best air/fuel mixture with my Dell'Orto 41mm carbs equiped with velocity stacks).

Thanks in advance,

Gilles
Author:  sports [ Wed Feb 18, 2015 3:25 pm ]
Post subject:  Re: Dyno Interpretaion
The kit I use is the Innovate motorsports 3845 MTX-L available from a number of sellers on ebay. Watch out because the other kit listed has a much longer transfer cable for the car fitment. It comes with a Bosch wide band Llamnda sensor, High quality cable and waterproof connectors and a steel female threaded plug to weld into the exhaust. All the kit to link it up to a data logging system too.
Fit the gauge up front somewhere, link it to an earth and 12v feed from the loom after the main switch. The first time you turn it on, it will run a diagnostic check for a free air reading. Bingo, that's it.

In a perfect world you would weld one plug in each down pipe, then take individual readings. However, we all know to run a slightly bigger jet in the rear anyway, as the front carb is almost flooding at rest. I just weld the one into the underside of the collector pipe at the back of the engine. You don't really see it there, and it is well protected from being damaged.

The gauge reads from zero to 22.4. The lower the reading, the richer the mixture. 12.5-13.5 is the goal, but clearly 12.5 is the safe side of the burn ratio so make up your own mind.

Technology, don't you just love it ?
Author:  618F1 [ Wed Feb 18, 2015 5:27 pm ]
Post subject:  Re: Dyno Interpretaion
Has anyone else tried using a Lazer temperature light (like the cheap one sold at Harbor Freight), by pointing it on both pipes about 3 or 4 inches from the manifold ring, and testing at a fast idle of 3000 to 4000 RPM? It is amazing how much the jetting can be improved by doing this test. Both pipes should be within 25 or so degrees, and around 500 degrees more or less. As you increase RPM (say 6000 RPM) the temperatures will go up, but they should stay close; if not then there is a too-rich/too lean situation. This was shown to me by an experienced engine builder (sand buggies) and machinist. I found it helped get things close in the garage setting.

I tested some of the F1s race bikes at the Symposium in NH in 2013, and almost all were very cold on the H pipe. Since these were experienced racers, and mostly time-tested machines, I kept quiet. But I wondered if jetting could be improved. MikeV
Author:  TheClaw [ Wed Feb 18, 2015 7:24 pm ]
Post subject:  Re: Dyno Interpretaion
Gents,

Very helpful. Thanks. I'll make some of the measurements Palmer suggested. Don't have all the tools for that but esay to come by (I have a birthday coming up, wife needs ideas). I haven't done much welding but I'm sure I could find the help to mount the AFR.

Jeff
Author:  marcotoys [ Wed Feb 18, 2015 7:41 pm ]
Post subject:  Re: Dyno Interpretaion
Thanks for your good advice Glynn !

I have found such a kit (Innovate Motorsports 3845) at a reasonable price on Amazon.ca and I have ordered it.

It will surely contribute to protect my pistons from overheating. A correct air/fuel ratio is very important for my engine considering that it now has a 12.0:1 compression ratio.

Thanks again,

Gilles
Author:  brad black [ Sat Feb 21, 2015 2:29 am ]
Post subject:  Re: Dyno Interpretaion
you need to start the run much lower, that way you get a better idea of the mixture across the range. 11:1 will kill a few hp on a dynojet. and you need to do runs until you get two consecutively "identical" runs. usually 3 is enough, but if it takes 5, do 5.

if it starts out lean and goes rich i'd say the carbs are maybe too small, or the main air bleeds need to be larger, but i've never tried changing that with dellortos, as it means drilling i think.

a guage is nice, but it's an unneeded distraction. get a data logger, do it properly. they're great.

ime, having run loggers on dyno as well as on the road, on non ram air things the results tend to transfer pretty well. but it might depend on the dyno room as much as anything else. logging on the road/track is the best way to do it overall.

i'd say 60 is about right for an f1. is there a reason you were expecting more?
Author:  TheClaw [ Sat Feb 21, 2015 8:52 am ]
Post subject:  Re: Dyno Interpretaion
brad black wrote:


i'd say 60 is about right for an f1. is there a reason you were expecting more?


The bike was originally built by Reno Leoni and raced for a good portion of its life. Been relatively idle last few years.
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