High octain causing more burble?

EGGMAN

EGGMAN

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SW OF TWIN CITIES,MINNESOTA
Last weekend we were snowmobiling up in Bayfield county. Perfect conditions! I have a 1998 700 xtc and my friend has a 2002 700 deluxe.
Both of the machines in the beginning of the trip ran about the same. It was in the mid to high twenties for temp. He ran 87 oct ins his machine and I foolishly paid more for 91 oct in mine. His did not have nearly the low speed burble that I had with the 91 oct gas. When I put in 87 oct after the day of riding the burble almost disappeared. Do you think I just got some stale fuel or was it the high octain?
 
I bet the fuel you got was high in ethanol. That stuff ruins 2 stroke engines and can cause that low end burble.
 
EGGMAN said:
Last weekend we were snowmobiling up in Bayfield county. Perfect conditions! I have a 1998 700 xtc and my friend has a 2002 700 deluxe.
Both of the machines in the beginning of the trip ran about the same. It was in the mid to high twenties for temp. He ran 87 oct ins his machine and I foolishly paid more for 91 oct in mine. His did not have nearly the low speed burble that I had with the 91 oct gas. When I put in 87 oct after the day of riding the burble almost disappeared. Do you think I just got some stale fuel or was it the high octain?
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87 octane (where I come from) usually contains ethanol which actually oxygenates the fuel.... 91 octane (where I come from) normally has no ethanol...

at mid to high 20's ambient, with all things equal (ie. jetting), you are running your sled rich in fuel/air mixture relative to him... his fuel is simulating a much colder day... (better performance)...

Research ethanol or lack of in 87 and 91 in your area... This could be consistent with your observations... tj
 
Do the reed notch, change out the stock jetting, raise the needle and the burble dissappears with any fuel even the 10% 87... Drop one tooth from stock and change the helix on the secondary and you wont be talking about fuel anymore...
 
Not knowing where you bought your fuel from, but yes you could have gotten some stale extemely old 91 octain fuel. If you bought fuel from a station which mainly sells to automobiles, the 91 could have been in the tanks since fall or even summer. How many automobile drivers are using 91 in the winter? Not many. I sure don't put 91 in any of my cars or trucks, I only use 91 in the Vette and it sure doesn't get out in winter. Anyway, if your sled is not modded and running stock jetting, run the 87 no problems. If you lean it out and mod it out, watch out. Al
 
unless your sled calls for 91 or higher your wasting your money period!the stories of vehicles running better on other than what THEY WERE DESIGNED FOR are just that, stories.
 
cougar1985 said:
unless your sled calls for 91 or higher your wasting your money period!the stories of vehicles running better on other than what THEY WERE DESIGNED FOR are just that, stories.
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Like I said before, I did waste my money. I think that most know that higher octain is not going to increase performance, in fact if anything it would decrease it on a sled not needing it. The only reason I have ever used it was to ensure not having a burndown on a two stroke. The other reason I have used it in the past is that at some stations it is the only gas that doesn't have ethenol. I had always thought it was cheap insurance. I had never in the past seen such a big performance difference as I did last weekend though. That being said, I am going to run cheap feul, unless I know it is going to be really cold, then I might still put in the higher octain for cheap insurance.
 
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