X31 octane?

brentn · 08-12-2010, 12:09 AM

Is it necessary to run 91 octane on the 2010 x31?

The engine I thought had a compression ratio of 9:1 which I'm positive only requires 87 octane.. But I'm not sure.

I ask this because I have a whole shitload of lawnmower gas in a jerry can that would be perfect for my girlfriends gio, 10 liter tank filled right up for her to have, which is only a couple weeks old. She can keep the tank and the gas and I don't have to buy another one taking up space in the garage...

So has anyone ran 87 in their x31 with an overhead cam engine (2010) with no pinging?

Weldangrind · 08-12-2010, 01:03 AM

I wouldn't.

I know that logic tells us that 87 would be fine, but that's based upon accurate specifications. Dump the jerry can fuel in the truck and buy some good stuff for the bike.

It's a little harder to start high octane fuel, but it burns a little cooler.

anthonyfa18 · 08-26-2010, 11:00 PM

i all ways run 94 octan in my 200cc beast

mizke · 08-26-2010, 11:05 PM

atv and dirtbike motors are supposed to run high octane gas only..93 to race gas..ive been thinking about buying a half gallon of some 103 race gas and seeing how the quad runs on it..

Weldangrind · 08-27-2010, 12:27 AM

That's only with high compression engines. Good luck starting a Beast on 103.

mizke · 08-27-2010, 01:12 AM

Quote:

Originally Posted by Weldangrind

That's only with high compression engines. Good luck starting a Beast on 103.

i will jump start it with my car, lol.. didnt know that it would make it hard to start.. mine fires up within 2 seconds of hitting the start button

Cal25 · 08-27-2010, 08:56 AM

I think the owners manual with my bike says not to run premium gas. Not sure that it would hurt anything though.

If an engine runs without detonation on regular gas, a higher octane wont add any performance.

Weldangrind · 08-27-2010, 10:26 AM

Exactly my understanding of octane ratings.

If you have a high compression engine and you have the ignition timing retarded to combat detonation, premium will allow you to properly advance the timing and take advantage of the compression. Otherwise, high octane fuel in a low compression engine is just expensive.

That said, I do run 94 in my Beast. It starts without too much trouble, and 94 doesn't burn as hot as regular. I give my little Beast every longevity advantage I can.

brentn · 08-28-2010, 08:18 PM

Running a higher octane can actually hurt performance because the compression on the head may not be good enough to fully ignite it.

Going to try some 87 tomorrow on it. If I hear any kind of pinging I'll stop it and roll it back to the truck and drain it out. I'll report back with my findings.

TurboT · 08-29-2010, 01:49 AM

Quote:

Originally Posted by brentn

Running a higher octane can actually hurt performance because the compression on the head may not be good enough to fully ignite it.

Going to try some 87 tomorrow on it. If I hear any kind of pinging I'll stop it and roll it back to the truck and drain it out. I'll report back with my findings.

I think it'll run fine with 87.

mizke · 08-29-2010, 02:22 AM

my quad ran freshly dumped steaming in middle of winter poopie when i ran 87 in it..

FosterVS · 08-29-2010, 01:06 PM

Quote:

Originally Posted by brentn

Is it necessary to run 91 octane on the 2010 x31?

So has anyone ran 87 in their x31 with an overhead cam engine (2010) with no pinging?

Pinging no, more backfiring... yes. At least that is what I noticed.

But that also could have more to do with taking the intake part, and reinstalling the gaskets and spacer right side up, instead of upside down, which blocked a good section of the intake. And gasket-sealing them before I reinstalled. And replacing the plug and wire...

I'm betting 87 octane would be fine

brentn · 08-29-2010, 06:23 PM

Dumped 3.9L of 87 in the bike yesterday and had it ideling fine for about 10 minutes solid. Bike was plenty warmed up and I started to give it a little bit of throttle and noticed no difference at all between this gas and the 91 I was using.

Going to take it out in a couple hours for an actual ride with the GF, so we'll see how it runs under load and more heat.
Will update when I know more.

So far 87 seems to be fine.

threemilesfinal · 08-07-2011, 11:53 AM

Anyone tried running 100LL AVGAS at all?

I used to get it for my 79 5.0L Mustang years ago and it purred like a kitten. Just wondering as I can still get my paws on it up here too.

Weldangrind · 08-07-2011, 12:49 PM

Good luck getting the engine to start with octane that high.

08-12-2010, 12:09 AM	#1
brentn Join Date: Aug 2010 Posts: 26	X31 octane? Is it necessary to run 91 octane on the 2010 x31? The engine I thought had a compression ratio of 9:1 which I'm positive only requires 87 octane.. But I'm not sure. I ask this because I have a whole shitload of lawnmower gas in a jerry can that would be perfect for my girlfriends gio, 10 liter tank filled right up for her to have, which is only a couple weeks old. She can keep the tank and the gas and I don't have to buy another one taking up space in the garage... So has anyone ran 87 in their x31 with an overhead cam engine (2010) with no pinging?
	0

08-12-2010, 01:03 AM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I wouldn't. I know that logic tells us that 87 would be fine, but that's based upon accurate specifications. Dump the jerry can fuel in the truck and buy some good stuff for the bike. It's a little harder to start high octane fuel, but it burns a little cooler. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

08-26-2010, 11:00 PM	#3
anthonyfa18 Join Date: Nov 2009 Location: montreal Posts: 242	i all ways run 94 octan in my 200cc beast __________________ 2008 gio beast 200cc mod list YTX14-BS battery mod,gy6 carb 250cc,custom intake,125cc cf dirtbike muffler,MPR filter/intake,performance cdi,ngk iridium xi dpr8eix-9,performance coil pack and wire, pro taper handle bar, Gio air shocks, yam swing arm bus
	0

08-27-2010, 12:27 AM	#5
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	That's only with high compression engines. Good luck starting a Beast on 103. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

08-27-2010, 10:26 AM	#8
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Exactly my understanding of octane ratings. If you have a high compression engine and you have the ignition timing retarded to combat detonation, premium will allow you to properly advance the timing and take advantage of the compression. Otherwise, high octane fuel in a low compression engine is just expensive. That said, I do run 94 in my Beast. It starts without too much trouble, and 94 doesn't burn as hot as regular. I give my little Beast every longevity advantage I can. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0

08-26-2010, 11:05 PM	#4
mizke Join Date: Aug 2010 Location: austin, tx Posts: 1,452	atv and dirtbike motors are supposed to run high octane gas only..93 to race gas..ive been thinking about buying a half gallon of some 103 race gas and seeing how the quad runs on it..
	0

08-27-2010, 08:56 AM	#7
Cal25 Join Date: Feb 2008 Location: Terrell and Grapevine Tx. Posts: 1,585	I think the owners manual with my bike says not to run premium gas. Not sure that it would hurt anything though. If an engine runs without detonation on regular gas, a higher octane wont add any performance.
	0

08-28-2010, 08:18 PM	#9
brentn Join Date: Aug 2010 Posts: 26	Running a higher octane can actually hurt performance because the compression on the head may not be good enough to fully ignite it. Going to try some 87 tomorrow on it. If I hear any kind of pinging I'll stop it and roll it back to the truck and drain it out. I'll report back with my findings.
	0

08-29-2010, 02:22 AM	#11
mizke Join Date: Aug 2010 Location: austin, tx Posts: 1,452	my quad ran freshly dumped steaming in middle of winter poopie when i ran 87 in it..
	0

08-29-2010, 06:23 PM	#13
brentn Join Date: Aug 2010 Posts: 26	Dumped 3.9L of 87 in the bike yesterday and had it ideling fine for about 10 minutes solid. Bike was plenty warmed up and I started to give it a little bit of throttle and noticed no difference at all between this gas and the 91 I was using. Going to take it out in a couple hours for an actual ride with the GF, so we'll see how it runs under load and more heat. Will update when I know more. So far 87 seems to be fine.
	0

08-07-2011, 11:53 AM	#14
threemilesfinal Join Date: Aug 2011 Location: HV-GB, Labrador, Canada Posts: 17	Anyone tried running 100LL AVGAS at all? I used to get it for my 79 5.0L Mustang years ago and it purred like a kitten. Just wondering as I can still get my paws on it up here too.
	0

08-07-2011, 12:49 PM	#15
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Good luck getting the engine to start with octane that high. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
	0