95 octane

Related to this discussion, I found on a Rotax engine website where they say that leaded fuel such as 100 LL aviation fuel can damage valve seats.

Here is the link and the text:

http://www.rotaxservice.com/rotax_tips/rotax_feed4.htm

Aviation Fuels

It is possible but not recommended to use 100LL AVGAS, since the the lead content is like cholesterol to your engine: it will accelerate wear on the valve seats, create deposits in the combustion chamber and sediments in the lubrication system and gearbox. Increased maintenance is necessary to compensate. Unlike "conventional" aircraft engines, lead is absolutely not essential to the proper lubrication and operation of a Rotax 4-stroke aircraft engine. The increased octane rating also has no marked advantage for the operation of your engine.

Related to this discussion, I found on a Rotax engine website where they say that leaded fuel such as 100 LL aviation fuel can damage valve seats.

I haven't heard of anyone that uses avgas in their 4 banger! :applause:

In one of the recent MX mags.; this question was raised by a reader....

The mag editors agreed for a number of reasons that I can't remember that using AV gas is a no-no.

AvGas is formulated for an engine that runs at very low rpms and at one steady speed for long periods, and which has a long intake tract. Aircraft engines also operate with vastly lower outside air temperatures. Because of these and other factors, the burn rates and vaporization rates are wrong. It just isn't an optimal fuel for a small, high revving engine with a short intake.

I haven't heard of anyone that uses avgas in their 4 banger! :applause:

It comes up around here from time to time. There are a small group of people here that swear avgas is the best thing since sliced bread and they argue it's safe for these motors even though there is a ton of evidence to the contrary.

A quick search should get hits on some of the discussions.

It just isn't an optimal fuel for a small, high revving engine with a short intake.
Makes 2 strokes seem like they have nitro!

That's what they say at Black Feather Racing.

Related to this discussion, I found on a Rotax engine website where they say that leaded fuel such as 100 LL aviation fuel can damage valve seats.

Here is the link and the text:

http://www.rotaxservice.com/rotax_tips/rotax_feed4.htm

Aviation Fuels

It is possible but not recommended to use 100LL AVGAS, since the the lead content is like cholesterol to your engine: it will accelerate wear on the valve seats, create deposits in the combustion chamber and sediments in the lubrication system and gearbox. Increased maintenance is necessary to compensate. Unlike "conventional" aircraft engines, lead is absolutely not essential to the proper lubrication and operation of a Rotax 4-stroke aircraft engine. The increased octane rating also has no marked advantage for the operation of your engine.

I'm very surprised to see a reference to increased valve seat wear due to 100LL use. I would really like to see an expanded explanation for this.

can i run 100 octane aviation fuel in a stock 2003 yzf 450

To make a long story short.....No, don't use Aviation fuel in your stock bike. You're wasting money, and also Aviation fuel is designed for Aviation Engines, not MX engines.

Just use 91 -94 octane gas from the pump.....Motocross Action Magazine answered this same question, and said stay away from AV gas.

Quick tip that I am sure a lot already know. Go to auto zone or your dealer and get some STA-BIL. It is a fuel additive. I worked in a machine rental company for years and we relied on this stuff. Mostly because all of the machines didn't go out as often as others or during the winter months. We added the STA-BIL to our fuel tanks (550 gal) and the gas stayed fresh for about a year. Made spring time pulling of lawn equipment (tillers,blowers,lawn mowers etc...) it makes the fuel look a little red, but if you are like most of us and get a 5 gal jug of fuel, just add this and you will have fresh gas when you need it.

Just some off topic info.

No, you can run the premium unleaded in your bike, the factory bikes run their own special blend of 95 octane but I am sure the ignition boxes and compression ratios are sigingicantly different than what we can get.

Then can get away with higher compression because they all run the slipper clutches.

Wow, V-Power is 99 octane? They do sell that here. They also sell race gasoline for cars, its like 110 Octane.

I just run premium, which is 97 here.

Quick tip that I am sure a lot already know. Go to auto zone or your dealer and get some STA-BIL. It is a fuel additive. I worked in a machine rental company for years and we relied on this stuff. Mostly because all of the machines didn't go out as often as others or during the winter months. We added the STA-BIL to our fuel tanks (550 gal) and the gas stayed fresh for about a year. Made spring time pulling of lawn equipment (tillers,blowers,lawn mowers etc...) it makes the fuel look a little red, but if you are like most of us and get a 5 gal jug of fuel, just add this and you will have fresh gas when you need it.

Just some off topic info.

I'll second this!! Sta-bil has kept my small motors (lawn mowers, weed eaters, motorcycles, boats even, etc etc) running fresh with even as much as 8 month old gas (after an overseas deployment, for instance). I believe in the stuff and use it religiously....because of that, I believe, is why I've never had to rebuild a carb after it's been in my care.

Cheap insurance!

Why's everyone thinking that higher octane is better for your bike? Does anyone know the octane numbers for U4? It isn't over 100... You guys are listening to car guys too much. Our bikes run great on pump gas - just jet accordingly. If you want "special" fuel and can afford race gas, run the U4 stuff. Unbelievable increases in hp and even though it is a bit of a hassle to drain and store, it is worth the cost and time.

Plus, for you AMA guys, they have a legal form of U4 for AMA racing...

Same theory holds true and even more so, for the sportbike stuff. MR9 and U4 are fuels of choice and again, guys running crap that is 110 and related octane are just wasting money... The only thing they are gaining is the smell.

First, not all AVgas is the same. Here is a site with some very smart people on it discussing AVgas, octane, grades, and use in all types of engines including the old engines and old gas and why engines and gas of the time can't be discussed across the board with equal generalizations. It also tells you how to get cheap AVgas from 'recovery':

http://www.arboristsite.com/archive/index.php/t-19016.html

As for stabil, you really don't need to 'add the red' as methanol 'yellow bottle of HEET' or acetone or toluene will work fine. All those will also boost your octane at 60ml per 5 gallons and will work in 2s or 4s. I like acetone as it smells better, but it's more expensive @ $12/gallon than $5/gallon for methanol from a drum or $10+/gallon if you buy it per 12oz Heet bottles. (the only problem with methanol is that over a long time it might draw water which is 'old' gas, though it still fights the varnishing and gumming.

You will have to experiment a bit, but if you add too much of any of those you will get a lean condition which you fix by backing the additive off a bit.

I ride every weekend on a YZ450F and been running the cheap stuff now for two years no problem. I've got a buddy on a 250f that has done this since 03.. So, I would have to say you don't have to run the high octane stuff, but that fuel from the airport does produce more power.... Maybe I'm just lucky, but the bike performs fine in the woods...

The bike was designed for 91 octane (R+M)/2 method; which is the standard method of measuring octane at the pump, in the United States.

I would not run below 91, since you may experience pre-ignition (knocking or pinging).

ya lost me on that one i just mix half92 and 115 sunoco and call it good motors runs good does not ping

i run 100 in my crf250

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