The 5 degree ignition advancer?
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If anyone has used one in conjunction with stage two jet kit I would be curios to know if you get any pinging or detonation either on or of the throttle. This would be on standard pump gas(91 octane).The rumour I heard was that it causes these problems but I didn't hear if the bikes were stock or with the afformentioned mods.
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Red01SuziB12S
(11/14/01 2:46 pm)
Re: The 5 degree ignition advancer?
The 5* advancer is a common mod and works well with a Stage I and should be part of a 'complete' Stage II. Since stock B12 pistons are fairly low compression units, 91 octane is unnecessary, even in a Stage II motor. It can actually cause more harm than good and lead to carbon build-up. Stick with regular. Your wallet will be happier and so will your motor!! Now if you have hi-compression pistons (stock bore or a big-bore kit) that would be a different story.
Paul W
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B12Teuton
(11/24/01 9:23 pm)
5+?
I was wondering about the same thing. My '01 B12 is bone stock, and I had read what Paul said, previously. When I filled the tank with regular for the first time, I found it knocked quite a bit. It was during very hot weather riding, and most noticeable in taller gears/lower RPM with a lot of throttle.
If you run the advancer, I would be weary if the highest octain you can find is 91. I usually ride a few miles farther, and pay a dollar more to fill it with Sunoco Ultra 94.
Realize also that in Europe, Regular is usually at least 91. Super at most pumps is often 98-100!!
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Red01SuziB12S
(11/26/01 6:23 pm)
Octane
I'm not sure if the octane in Euro fuels is really any higher than what we have in the US. I think it is due to the way the US pumps advertise their octane levels. Federal regulations require US pumps to display octane as an average of its Research Octane Number (RON) and Motor Octane Number (MON) which creates Pump Octane Number (PON). This makes the numbers lower on US pumps than on European pumps - which use only RON.
Paul W
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B12Teuton
(11/26/01 8:56 pm)
Octane and +5 advancer
I know that aviation fuel uses a different formula to calculate octane. However, cars built and sold in Europe have a minimum octane rating in the owners manual. The same cars sold state side have the same minimum octane number in the manual.
Either way, it comes down to personal preferance and experiance. My stock Bandit knocked a lot on regular 87 octane, so I only get 93+. If yours does not, either you are lucky or have slightly lower compression. I don't have a 5* advancer, but any time you have a stage 1 or 2, you are making the environment inside the combustion chamber hotter and more voletile. It would only stand to reason that performance would benefit from higher octane, to inhibit combustion until the perfet instant, ignition. I guess it is also possible that I got a tank of bad gas. I don't know. As far as the carbon build-up, I don't know either. I ride fairly hard and rarely have a ride where I don't have a full throttle run through the gears. I have not pulled my motor apart yet, but I would be supprised to find any carbon build up. Plugs are clean.
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Owen69
(11/26/01 9:54 pm)
The 5 degree ignition advancer?
Tell me if I am wrong, but adding a jet kit puts more fuel into the engine therefore it is making it rich. Does this not make the engine run cooler? Such as when you run a lean mix you have a higher case of burning a plug.
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Red01SuziB12S
(11/27/01 1:25 am)
More on octane than you probably wanna know ;)
Yes, running richer will lower an engine's operating temp. Excessively lean conditions can cause problems even worse than burning a plug - they can even burn holes in pistons (don't ask me how I know this )
Yes, AvGas octane is rated different from ground fuels. Commonly rated in a dual number system, like 80/87 and 100/130 (as well as a few other obsolete ones), the first number is the fuel's lean mixture rating, while the higher number is the rich mixture rating. 100/130 & 100LL (low lead - 1/2 the lead of 100/130) both have octane ratings of ~100 when tested to automotive standards, but it is a lighter, less volatile fuel than a comparable ground fuel. Normal ground level fuels are made up of gas molecules that have a "light end" and a "heavy end" and AvGas only has the light end (primarily to save fuel weight). The light end of the molecule ignites easily and burns quickly with a low temperature flame (as a piece of thin newspaper would burn). The heavy end of the molecule is not so easily ignited, but it burns with a much more intense heat (as an oak log would). This heavy end of the gasoline molecule is responsible for the hotter, more powerful part of the combustion process. Since gasoline aircraft engines turn very low rpms and produce so little power for their displacement, the omission of the heavy end is not a big horsepower issue for these engines.
Octane numbers higher than 100 are found by measuring the amount of tetraethyl lead that must be added to pure isooctane to duplicate the knocking of a sample fuel. You can't get over 100 octane fuel with only isooctane.
Paul W
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Topic: The 5 Degree Ignition Advancer and OCTANE info (Read 13342 times)