Fuel: Ethanol vs. Non-Etahnol

Ethanol can cause some issues in the fuel system and is generically not recommended for small engine stuff across the board.  Several reasons jump out so pick the one that bothers you the most.

It dries out rubber seal like o rings and fuel lines which can cause cracking/leaking but it takes some time for new seals and lines to develop that.

It can attract water.  This causes it to have a shorter "shelf life" that regular gas, like 1-2 months as opposed to 5-6 months.  Plus, it can attract water in the bike's fuel tank as well, introducing small amounts of water into your fuel system directly.

The other issues tend to have effects on older engines and carbs.

Short term, you won't notice an issue.  The oxygenated, higher octane w/ ethanol and a remap will probably run great.  But if the bike and/or fuel sits for a bit you could start running into problems. 

I run crappy pump gas w/ ethanol in my commuter car all the time.  It's and old car and gets better gas mileage than my truck. It usually only sits for a few weeks a year while we are on vacation.  I've never noticed major issues with it but I also don't expect high level performance out of it either.  The bike gets ethanol free only, had a fuel pump go out but its a known common problem.  No other fuel problems that I've noticed on the bike.

This is a good podcast with Keefer and Chad from XPR. They talk a lot about fuel.

https://www.keeferinctesting.com/show-297-engine-building-talk-myths-and-facts/

See if you can find Sunoco 260 GTX out of a pump near you. 

You need to remap for non-oxygenated fuel or it is going to run rich. Oxygenated fuel adds power too so you are going to lose some snap no matter what. I have not had issues with ethanol in fuel injected engines. I had a 2023 FC250 that ran better on pump fuel than non ethanol fuel. It isn't that hard to get the fuel out of the system at the end of the season if you are worried about it.

I won't run it in a carb because carbs don't like ethanol or the water that can come with it and a lot of carbs are from before the ethanol era. Having said that I have been running some pump fuel in my lawnmower which has a Kawasaki carb engine and no issues yet. It is newer and rated for 10% ethanol so it should be fine but I still run the carb out of fuel at the end of the season and try to run non ethanol fuel for the last couple of cuts.

Been running Sunoco 260GT (100 octane, has ethanol) in my '18 CRF450RX for years. It sometimes sits for months without being run. Haven't had any problems from ethanol yet.

You have to remap for higher octane fuel like you’d have to re-jet on the 2 stroke. All the new bikes are mapped to run off pump gas. You can usually run them from the high 80s to low 100s but anything over that needs some help. Higher compression and higher octane need the mapping. 

I can’t get non ethanol where I am or within any reasonable amount of drive, I always run startron, I think is the name, ethanol guard. And I always get fresh gas the morning of riding. Dump the old stuff in my truck 

I’ve run non-ethanol 93 octane pump gas from a local gas station for years with no problems. 138 hrs on my 14 KTM450sxf. 99hrs on my 19 KTM350sxf. And now 79hrs on my 22 KTM350sxf. If you wanna spend the extra $ on race gas, I trust that it is beneficial. But I can use the extra $ for tires, etc. so have been happy and trouble free with what I run. 

I too have a local station that sells non ethanol fuel from a pump in 93 octane. Are y’all saying I need to remap the bike to run that gas? Bike feels great on that gas. 

Have you tried it with e10 93? It may have better throttle response with oxygenated fuel. If you like how it runs now no reason then change though. Ethanol free is usually going to run richer which should not hurt anything. 

This is it... It ain't that deep. Unless you're running a highly modded engine that calls for the fuel, just run pump or a bucket of T4 and don't over think this. 

We run non-ethanol 90 in our bikes and have zero issues. Save the money from race gas, you’ll need it somewhere else in this game 😂

Is there a power loss going to a lower octane without ethanol? Say a 93 with Ethanol vs a 90 without? 

Probably a power gain actually. Ethanol fuel requires about 33% more fuel to make the same power as ethanol free gas. In either case it’s not enough of a change that you’ll ever feel a difference. 

Ethanol adds oxygen and stock bikes are tuned to run on 10% ethanol. When you take out the ethanol you richen the mixture and lose the oxygen. It should make less power. You may be able to mitigate this somewhat with tuning to get the a/f ratio back to where it was. If you retune you should get better mileage but maybe not enough to really be able to tell.

I've run 93 octane pump fuel with ethanol and 90 octane pump without ethanol in a back to back comparison before. My bone stock MC 350 with stock mapping actually seemed to run a little bit crisper with better throttle response when running 93 with ethanol. It was not a major difference and I run the 90 non ethanol most of the time because I use it in all my power equipment. 

I heard a rumor once that if you alternate ethanol and non ethanol fuel it can potentially dry out and crack your seals and hoses

Never heard that before. If anything, it would be the prolonged use or long term sitting of ethanol that would cause problems. 

You need Rec 90 aka marine fuel. No ethanol, my bike runs the same on it as it does on 93. I dont live near a marina but luckily i live near a place that has it on pump.

If you have an airport nearby, you might be able to get some UL94 which is close to 100 octane and ethanol free. They might have 100LL depending where you live.

I ran pump gas in my 17 450sxf for over 100 hours without issue. For my rm250, I usually do 50/50 pump/UL94 and always have the carb empty when it’s sitting. Also had the head squish done to prevent detonation from pump gas and just checked the head the other day after 25 hours and there wasn’t any detonation. So far so good. 
 

if you’re racing competitively then you should definitely run race gas or if you can afford it and have access to it. 

www.pure-gas.org

Hit the index, find your state. All the locations are listed alphabetically by city. I think there’s a map function but I’m not positive. 

Non ethanol pump makes less HP from what my local shop says from his dyno but probably not noticeable on a 450