I Spy With My Little Eye...

Tornado said:
Ouwie! Was that from a wrist pin clip going adrift?
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Yes...clip broke, gouged one side then traveled through the pin and got the other side
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I Spy With My Little Eye...
I Spy With My Little Eye...
 
Tornado

Nothing to worry about. Could be the tune, or a little of what mdt-son mentioned.

Could be the fuel too. The 89 octane non-ethanol fuel they have around here makes my engine a little anemic, which is why I don't use it.
 
mdt-son said:
Please consider the possibility of a "leakup", i.e., valves not seating properly, or eroded seats/valve rims.

- Knut
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Is this what a "leak down" test does, using a compressor while vlaves fully closed to monitor how pressure is held/not held or is leak up something different?
 
Schwany said:
Tornado

Nothing to worry about. Could be the tune, or a little of what mdt-son mentioned.

Could be the fuel too. The 89 octane non-ethanol fuel they have around here makes my engine a little anemic, which is why I don't use it.
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"89 octane non-ethanol"? Do you mean you avoid ethanol fuels?
 
kommando said:
Not that it explains the difference but for EI you can time to 31 BTDC at the EI's recommended revs not the 28 BTDC at 3K for points. Once fully advanced the points stop advancing, for EI its a curve where at high revs its still advancing very slowly but you can use more advance as the wander of the points is missing and there is no difference for side to side timing due to the self correcting of using 2 magnets on the rotor and 2 sensor coils on the stator.

Wassell instructions for Norton twins is 28 to 31 BTDC at 4 to 5K.
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Yes, the Wassell guide shows 28-31. When I tried tweaking it a bit more than 28, I had kickbacks. But will need to go through the whole process, timing disc/TDC with piston stop etc to check the primary case scale (previously damaged, to be replaced). I've replaced the alt/rotor since last timing setup, so the marks on rotor might also be off compared to original.
 
Tornado said:
Is this what a "leak down" test does, using a compressor while vlaves fully closed to monitor how pressure is held/not held or is leak up something different?
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Sorry for the confusion. It was an invented term to point at the possibility of valve leaks!
A "leak down" test will detect both (piston ring and valve seating), and it will be difficult to decide where the leak is. In a secondary step, you need to inject oil in the combustion chamber to eliminate piston ring leaks.
Testing for valve leaks in situ isn't easy by other methods, AFAIK.

- Knut
 
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Tornado said:
"89 octane non-ethanol"? Do you mean you avoid ethanol fuels?
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No, I avoid 89 octane "non-ethanol fuel". I have zero issues using 92 octane e10 pump gas.

You mentioned your engine felt down on power. That is what my engine feels like when I use 89 octane "non-ethanol fuel".
 
That's weird as the lower Octane fuel has more a bit more energy per unit of volume than high Octane does.
If the 89 Octane is allowing pinging to happen, then that would change things.
Non ethanol also adds energy or, the easier way to look at it is that adding ethanol to gas reduces its energy. Ethanol has substantially less energy per unit than gasoline does.

When I tried out different fuels on dyno hill my best result was with a 91 Octane Ethanol free gasoline. Next best was with Chevron 94 ethanol free ( no longer available)
I could not find any 89 Octane ethanol free to test. I suspect it would have given the best result.
All of the fuels containing ethanol made the bike a bit slower.
The worst was Shell Premium with 10% ethanol. I believe that knocked off 4 kmh at top of hill.
Glen
 
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worntorn said:
That's weird as the lower Octane fuel has more a bit more energy per unit of volume than high Octane does.
If the 89 Octane is allowing pinging to happen, then that would change things.
Non ethanol also adds energy or, the easier way to look at it is that adding ethanol to gas reduces its energy. Ethanol has substantially less energy per unit than gasoline does.

When I tried out different fuels on dyno hill my best result was with a 91 Octane Ethanol free gasoline. Next best was with Chevron 94 ethanol free ( no longer available)
I could not find any 89 Octane ethanol free to test. I suspect it would have given the best result.
All of the fuels containing ethanol made the bike a bit slower.
The worst was Shell Premium with 10% ethanol. I believe that knocked off 4 kmh at top of hill.
Glen
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Too lean can cause missing and lead to engine damage, but the slightest bit too rich anywhere, and the motor will be slower. Fuel quality changes affect jetting requirements.
 
Yes, I played with jetting on each fuel test, same as with the silencers. The only difference was that with the fuel tests the 260s were the best right across the board. One up or down slowed things down.
I've gotten quite good at changing mainjets quickly.

Glen
 
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Providing the compression test is reading sensible amount of compression and both sides are within 10% of each then I would not worry too much. Does it pass when doing a leak down test? if not then it is worth checking out. The damage is seen in a lot bikes and I suspect it comes from debris dropping through the plug hole when the plugs are removed - always ensure the area around the plug is clean prior to removal as it acts like a shelf for road grit and dust.
 
worntorn said:
That's weird as the lower Octane fuel has more a bit more energy per unit of volume than high Octane does.
If the 89 Octane is allowing pinging to happen, then that would change things.
Non ethanol also adds energy or, the easier way to look at it is that adding ethanol to gas reduces its energy. Ethanol has substantially less energy per unit than gasoline does.

When I tried out different fuels on dyno hill my best result was with a 91 Octane Ethanol free gasoline. Next best was with Chevron 94 ethanol free ( no longer available)
I could not find any 89 Octane ethanol free to test. I suspect it would have given the best result.
All of the fuels containing ethanol made the bike a bit slower.
The worst was Shell Premium with 10% ethanol. I believe that knocked off 4 kmh at top of hill.
Glen
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That's not exactly what the definition of octane rating actually says. It says that they have the same amount of energy per measured volume, and it says that the octane rating is amount the fuel will resist detonation from pressure applied to it. It also says that this can lead to more power in high compression engines,... presumeably because the high compression engines benefit from the higher resistance to detonation and not because there is more energy per measured volume....

WTBS, when you do your testing, the only thing you can conclude is that,... Given your bike's compression and timing, a certain fuel gives your configuration the best power performance. BUT, if you look at the easily found information about octane in fuels, the information suggests that a higher octane fuel can give better performance in a higher compression engine... As with most engines, all the variables effect what works best.

I have always used the 91 high octane non-ethanol fuel in my commando. My engine has no base gasket and a composite head gasket. I always just assumed that I needed the higher octane fuel for higher compression. I think I'm going to experiment with the different fuels (both eth and non-eth) this coming year to see if I notice any difference.
 
The Octane rating has nothing to do with the energy per volume.
The higher Octane fuels resist preignition by burning a bit slower. They also contain slightly less energy per volume, but it's not a great amount.
People commonly think it's the other way- high Octane = high energy.
You only need the Octane level to be as high as necessary for your engine.
Going above that level won't hurt anything, but it will give you slightly less power.
The above information is for older engines.
With some new very high compression computer controlled engines the Octane level of the fuel is measured instantaneously and timing is adjusted back if lower Octane fuels are used. With those engines more power is available with high Octane, but it isn't due to extra energy in the fuel, it's due to timing and fueling chosen by the computer.

Glen
 
Twenty years ago when I asked for and received energy numbers for 3 Octane levels from our local supplier, the gasoline they were supplying was all ethanol free. The regular gasoline contained the greatest energy, migrade next and premium had the lowest amount of energy per litre. The difference wasn't much, but it was there.
I suspect the difference is greater now that ethanol is used in almost all fuels. Their premium grade now uses about 10% ethanol while midgrade was at 7% and regular at 5% ethanol, according to my measurements.
The use of more ethanol in the higher octane fuel is pretty common now as ethanol works to raise octane ( slow the burn). It also lowers the energy density of the gasoline, so you won't go quite as far on a litre of premium with 10% ethanol as you would on regular with 5% ethanol.
Of course on zero percent ethanol regular gasoline, if you can find it, you will go even farther on a litre, provided your engine is designed to run ok on 89 octane.

Glen
 
I know you boys and maybe girls love ethanol free fuel. I personally have no problems using e10 Premium in the Norton I ride.

The 89 octane ethanol free fuel did not make my engine ping it just felt kind of flabby to me. Could be the fuel I bought that day wasn't all that fresh coming out of the pump or my tune is not ideal for ethanol free fuel. I don't think the station I bought it from sells a lot of it on a daily basis, because it is priced about $1.50US more per gallon than Premium e10. I think the gardeners use the ethanol free fuel for their fuel powered leaf blowers and lawn mowers.

I could always tell when I put race gas in the motorcycles I have owned. It always made a distinct difference I could feel. Fairly certain it was much higher octane among other things.

Do the racers that visit this site put regular ethanol free 87 octane fuel in their race bikes for that added dyno hill energy?
 
Schwany said:
Do the racers that visit this site put regular ethanol free 87 octane fuel in their race bikes for that added dyno hill energy?
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probably not as it could cause serious problems in a very high compression engine.
As Nortonbob pointed out- my hill testing only shows what works best in my bike.
I should remember that and perhaps not try to share info that might or might not work for others.

Glen
 
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