Dyno tuning Amals

worntorn said:

If you are a stickler for perfection,use an O2 sensor, not a Dyno. A Dyno can get you there eventually, but compared to the sensor it is like groping around in the dark vs bright sunshine.

Glen

Click to expand...

I was under the impression that a dyno run would include measuring how rich or lean the gases coming out of the exhaust were, giving the opportunity to check pilot, cutaway, needle and main jet mixtures depending on throttle position. The hp and torque graphs being mostly for verification that the carbs are set up correctly. Or am I wrong?

There is an old saying 'what gets measured gets managed'

Click to expand...

Yep sir same thing in medical tests - can vary significantly on which side of body a sample taken for blood, time of day and brand of equipment. Imaging diagnosis is similar with conflicting opinion calls unless an obvious bullet, fracture or parts missing, then more opinion calls to decide what if anything to do about it.

Dynos suck for low rpm reading below 2000 such as a road bike needs most fine tuning on. O2 senors and types have many issues to learn about to interpret their readings and can give readings all over the place on less than WOT runs. The better dyno shops use multi-gas analyizers on long stalk to get close to head exits to avoid back flush of atmosphere. If you are of the mind set to baby a new born Norton engine on break in and brag never exceeding red line you may mess your shorts on what a worth dyno run takes. A good ear or knock sensor, a stop watch or G-meter over a marked distance road plus CHT and EGT with wide band 02 allows DIY to get it pretty darn right. Plug chops on new age gas only helpful for way out of tune indicators and heat range selection after final good tune settled on. Heat range of plugs makes a lot of difference on CHT too.

Rohan said:

acotrel said:

My approach is to ride the bike many laps of a race circuit and count the gear changes, you usually know if you are getting there quicker. The straights get shorter and the bike gets harder to stop.

Click to expand...

So does your RACE in/experience with METHANOL count for anything when tuning a ROAD bike for PETROL. ??

As has been pointed out previously, many times, methanol is very forgiving as far as tuning goes.
It can be 50% too rich, according to no less an authority than Phil irving, and still work OK.
Without that O2 probe, you wouldn't know...

Click to expand...

Rohan, in the end it is about energy output and combustion temperature and detonation. Regardless of whether it is petrol or methanol maximum energy output is just before the mixture destroys the engine. If you are using NGK 9 plugs in a Norton engine with standard ignition advance (28 degrees) and compression ratio ( 9 to one) and lean off the midrange as much as you can without getting the cough, you will get maximum acceleration, regardless of which fuel you are using. The next thing to consider is the main jets. If you run the bike hard on full throttle over a long distance on a slightly uphill road, you create the most extreme combustion conditions. A plug chop with the correct range of plugs shows whether you are starting to do damage (get detonation) as you lean off the jetting - as long as you don't meter off the tip of the needle.
With methanol, you are using twice the flow through the jets and thus have twice the margin for error. Getting it really right is just as difficult (?) as with petrol. The trouble is that with petrol the rich mixture makes the motor bog down more easily - it will still perform under those conditions with methanol.
A lot of guys use methanol in Australia and never find out how good it can be if it is leaned off correctly. Phil Irving did them a disservice with his comment about running methanol rich. He was correct, you do still get good performance running methanol rich, however NOT THE BEST PERFORMANCE. The trouble with any off this stuff is that if you get the mixture correct right throughout the whole range of throttle openings, you have to watch the weather. With my brother's Kawasaki H2 two stroke, a very cold night at the speedway is a worry. It is on methanol and as lean as buggery - a danger to mankind. You don't need a bike as fast and nasty as that anywhere. The trouble with tuning a two stroke like that is the costs of the mechanical damage getting it there. He also has an H1 on methanol and that is enough to win any race - you don't need the H2, it is too much.
With the Vincents and the 880 JAP on speedway we tend to stay with the old too rich situation, it is a different game. The bikes are all fast enough to compete fairly well with each other, however I suspect my brother has leaned off the JAP, it is much faster than the Vincents, and I wouldn't expect that to be the case with a motor that old in design.
With my 850, the difference on methanol between being lean and rich is very noticeable if you are sensitive to it. Usually while you are jetting, you also change gearing. The situation can be very deceptive.
One thing you might note about methanol. In the 1950s and 1960s it was used extensively in Australia and because of it we developed some very fast riders. When they went to England to race, they found the Brits got their Norton Manxs going as fast on petrol as we ever could in Australia on methanol. It meant that when our guys went there they were used to the speeds. Thank you Phil Irving - NOT.
Rohan, If you ever tune for methanol fuel, treat it the same as for petrol and the bike will be much faster than if you leave it rich. Any dill can use methanol and get the bike going three-quarters fast.

I can believe in the oxygen probe if you get a bike going very fast on a particular fuel, take a measurement then work backwards for other bikes. In effect calibrate it off a fast motor.

Roadrash said:

worntorn said:

If you are a stickler for perfection,use an O2 sensor, not a Dyno. A Dyno can get you there eventually, but compared to the sensor it is like groping around in the dark vs bright sunshine.

Glen

Click to expand...

I was under the impression that a dyno run would include measuring how rich or lean the gases coming out of the exhaust were, giving the opportunity to check pilot, cutaway, needle and main jet mixtures depending on throttle position. The hp and torque graphs being mostly for verification that the carbs are set up correctly. Or am I wrong?

Click to expand...

I guess it would depend on the equipment available at the shop used. If they use an engine gas analizer along with the dyno, then yes, that is the case. My own experience of Dyno tuning is limited to watching a friend's bike being dyno tuned without any other test equipment, just the dyno. That was a very expensive deal and didn't yield much, really poking around in the dark.
The nice thing about using the welded in bung, O2 probe and reader is that the readings are taken on the road in use rather than a simulated situation.
Glen

On Alans off topic rant, all we can do is repeat that lean mixtures don't produce maximum power.
As has been detailed in previous threads. Many previous threads.

And you have lotsa trophies for wins to back this up ??

I wish to add some factual information regarding the rich/lean = horsepower discussion

I have a 2012 Triumph Bonneville, EFI (no carbs)

I have it set up with aftermarket mufflers(not as restricted as stock) and the air box baffle removed along with a K&N air filter (to increase induction)

Because I have not changed the original stock engine management MAP, I am "lean"

Two months ago I brought the bike to my Triumph dealer for a dyno test

They ran it up to 6500rpm at full power and gave me a printout

The printout shows that my bike put out 61 horsepower at the rear wheel (stock is 52)

The printout shows that my bike's air/fuel mixture was a "lean" 15 parts air to 1 part gas.

This is versus the "ideal" air fuel mixture of right around 12.8 to 1

The Triumph service manager stated that his dyno consistently shows that bikes that
have a leaner air/fuel mixture put out more horsepower

He also assured me that my 15 to 1 mixture was by no means "too lean" as in no danger of overheating or engine damage, and we live here in HOT desert southwest USA

He said that people all the time assume that a richer mixture means more power, he says the opposite is true, to the point when the mixture become too lean and then power starts to fall off. He said that mixture figure was around 16 to 1, what he termed too lean

He also said that, based on his dyno tested identically set up EFI Bonnevilles but with the air/fuel mixture mapped to the standard 12.8 to 1, that mine produced 2.5 more hp

How useful, a fuel injected comparison to a Commando ?

And there is lean, and lean.
Cars (some cars) with injection (watercooled of course) can run fuel-air mixes down to as lean as 24:1
In cruise mode.
But try getting them to accelerate with them that lean....
And some can also switch off cylinders.

And as anyone with a Commando will know, try setting them up with the correct jetting,
then drop the needles and fit smaller jets sizes and try to get them to pull as strongly.

We have had this discussion here before, and someone quoted the typical fuel-air mix that Commandos run.
Someone also showed the dyno charts and fuel mix readouts.
Don't forget that Commandos don't have a hope in hell of meeting the current emission requirements,
they are not exactly the cleanest engines on the block anymore.

***If you could simply lean them out and they'd go faster, the factory might have noticed that too ?? ***

PPS The aftermarket chips you buy to give your injected rocketship that extra boost don't get all that extra power by running them leaner,
they pump more fuel in = more power out.
This concept that you can give them less fuel and get more power is going to have to be explained by someone, it ain't science...

How useful, a fuel injected comparison to a Commando ?

Click to expand...

correct, a Commando is not fuel injected

and nowhere in my post did I state any facts or dyno findings about a Commando

however, what I did do is to provide personal verification through a dyno test that horsepower can be optimized by setting the air/fuel mixture more on the leaner side of the supposed ideal of 12.75 to 1 than the richer side

if anyone has verification, and not personal projection, otherwise that shows more hp is developed on the richer side of the "ideal" versus the leaner, then come forth with it

by the way, my 865cc twin cylinder Triumph is hardly a rocket bike at only 61 hp

what fuel injection DOES do is allow more a more efficient and more measurable computer controlled air fuel mixture, bike to bike set up the same, allowing more consistent and more credible comparisons when comparing horse power and torque figures at various rpms tested on dynometer

Colorado Norton Works is now selling Jim's EFI set up for their Commandos

1up3down said:

the supposed ideal of 12.75 to 1 than the richer side

Click to expand...

Ah, but where have we plucked that 12.75:1 as the ideal. ?

I understood that was well on the rich side ...
Stoichiometric fuel/air ratio depends on the exact brew of gasoline/petrol,
but is somewhere in the range of 14 or 15 to one ??

(This has been discussed before, so this is a repeat of a repeat of a repeat)

And what would your Triumph have put out if you had chipped it,
and richened it up.

You had removed the restrictions in it, to so gain some power,
But had not done the rest of the equation...