Running 87 octane

[AmateurSawer]

I have bulk 87 octane here which is non alcohol but no one nearby has 89 or 93 octane in anything but 10%.I know Stihl and others recommend 89 but to buy it without ethanol,I'd have to drive 20 to 30 miles one way.
Am I risking anything beside performance using my 87 and Stihl Ultra ? Even if I get several cans I'd be concerned about stale fuel even though the synthetic mix has a stabilizer.

 

[Matt93eg]

Lots here run 87 without issues. Lots of threads in the searches.

 

[Jed1124]

I have bulk 87 octane here which is non alcohol but no one nearby has 89 or 93 octane in anything but 10%.I know Stihl and others recommend 89 but to buy it without ethanol,I'd have to drive 20 to 30 miles one way.
Am I risking anything beside performance using my 87 and Stihl Ultra ? Even if I get several cans I'd be concerned about stale fuel even though the synthetic mix has a stabilizer.

If your saw is old and has a lot of carbon buildup it is possible you could have some detonation. I’ve never heard of detonation being a problem on a stock saw with a proper timing setting, but it is possible.
You will lose no performance at all.

 

[Woodslasher]

All I run in my saws is 87 octane with Husky/Stihl mix oil and they work just fine. The only time an issue arises is when my neighbor fuels one up with his 110? 112? octane race gas and the saw falls a little out of tune.

 

[stihl86]

I have bulk 87 octane here which is non alcohol but no one nearby has 89 or 93 octane in anything but 10%.I know Stihl and others recommend 89 but to buy it without ethanol,I'd have to drive 20 to 30 miles one way.
Am I risking anything beside performance using my 87 and Stihl Ultra ? Even if I get several cans I'd be concerned about stale fuel even though the synthetic mix has a stabilizer.

You should research what octane does.
You'll never hear detonation in a 2 cycle.
89 provides a reasonable cushion of safety.
93 is a waste of money. It's not needed.
Unless the saw if modified

 

[drf255]

Even modified go with the 87. It will make better power and not detonate.

Even hopped up saws in the 240 psi compression range are only around 7:1 compression ratio.

 

[rarefish383]

87 only here. I hate having different cans of fuel. Every thing else uses 87, so that's what the saws get too. I use Stihl synthetic. Maybe if you use low grade fuel, low grade oil, the lowest denominator on every thing it will be a bigger problem. I have saws from the 60's to 2 years old and they all do well on 87.

 

[Ryan'smilling]

I wish I could find e-free 87. I'd run it all the time.

 

[AmateurSawer]

Thanks for all the replies. I feel better about what I'm using.

 

[Goofaroo]

87 will burn cleaner. You only need higher octane if you get preignition. The higher the octane the less volatile the fuel is. It only burns cleanly under very high compression and/or advanced timing. 87 is your friend and you’re lucky to have access to non ethanol 87. I am fortunate to have it available very close to me. I use it in everything I own including my dirt bikes.

 

[sunfish]

8 7 E free is what I'd prefer, but only 91 here. You're good to go!

 

[Matt93eg]

I just saw a place 10 mins from my house now selling e free 87. Nice to know it's there

 

[a. palmer jr.]

We only have 91 around here (20 mi.) and it's much better than the ethanol stuff so I drive 20 miles to get the good gas..

 

[RTK]

I like 100LL, no need for that high of octane, it never goes bad and I don’t ever have to drain the fuel for storage.

 

[lostone]

I have 88 e free 5 minutes from me and 91 e free about 15 minutes from me. I tried the 91 one time and have just been using the 88 e free since then.

 

[Brushwacker]

I am sure 87 will work fine in most conditions and many use it. I prefer 90 +.Back in my motocross days i remember pinging when using less octane. My understanding your engine runs cooler,more octane,my experience cooler engines put out more power then they do when they are hot.

 

[Goofaroo]

I am sure 87 will work fine in most conditions and many use it. I prefer 90 +.Back in my motocross days i remember pinging when using less octane. My understanding your engine runs cooler,more octane,my experience cooler engines put out more power then they do when they are hot.

The only competition bike I’ve ever owned that benefited from higher octane was my GasGas trials bike. It would get warm due to the low speed nature of trials competition. Racing fuel is designed to run cooler and still burn efficiently so I would use a 50/50 blend of race gas and pump gas.

The only time I’ve ever had a preignition problem on any other engine was due to mechanical issues such as carbon buildup, timing issues, or air leaks.

In general, the lowest octane you can find at the pump will be the best choice. In the vast majority of engines it will burn more completely and reduce carbon buildup and pollution output.

Obviously the lower octane fuel is capable of producing more power but the difference between 87 and 91 is negligible. The main difference will be the cleanliness of the burn.

 

[Tinman204]

I run E free 91, I'd run 87 but theres no E free 87 here so im stuck.

As for never hearing detonation in a 2 stroke thats not true at all.

I have an 1983 yz490 and if ypu run low octane in that bike you can hear it ping even with good ear pro on..

 

[Goofaroo]

I run E free 91, I'd run 87 but theres no E free 87 here so im stuck.

As for never hearing detonation in a 2 stroke thats not true at all.

I have an 1983 yz490 and if ypu run low octane in that bike you can hear it ping even with good ear pro on..

Absolutely. A 2 stroke can definitely ping.

I ran a 88 model YZ490 in the 89-90 Best in The Desert Series. No matter how much I fattened it up I had to be very careful or it would seize. On high speed sections like dry lake beds I would occasionally hold the kill button and hold the throttle wide open to suck in some fuel to cool and lubricate the top end. On the occasions it seized it would start up and go again after a few minutes of cooling off. lol