[i]too[/i] High Octane?

[Thugorp]

Hi again, So about a week ago(before I joined the forum) I bought a spree, when I bought it the tank was almost empty. The man I bought the vehicle from told me he filled it with 90 octane gasoline(apparently the highest octane available in Wisconsin) When I got home to the Chicago area(and boy was it good to be back. know?) the available octanes were 83, 89, and 93. I put in 89, and was a little disappointed, that my speed actually did seem slightly decreased. On the next fill I used 93 octane, the difference was immediately apparent, and I actually got up to thirty fives on strait-aways fairly regularly. Here is the thing though, soon after I started noticing that it was backfiring and sputtering at the low end. I am wondering if this is related and what is the optimum octane I should be using in my spree/can using a higher octane actually hurt it?

[bakaracer]

higher octane won't hurt the engine. double check the compression with a compression tester. if its high,then there is a high carbon build up on the piston and head.

[Thugorp]

I am glad to hear that the higher octane wont hurt the engine. This brings me back around to a new question though. I have ZERO auto-mechanical skills, does anyone know a good motorcycle/moped mechanic in the Chicago area?

[odinxxix]

nothing like doing it yourself. with the info on here you can do it. and at the fraction of the cost

[Bear45-70]

With the stock 7.2 to 1 compression ratio of the Spree, plain old regular, 87 octane gas is way more than enough. High octane can actually cause issues, so don't use it. When you use a big bore kit the, if you want, go ahead, but a stocker is a waste of money and asking for trouble.

[Clivester]

The primary reason for using high octane is to prevent pre-ignition (sometimes called pinging in cars) that can occur in HIGH COMPRESSION engines. There's no more power in higher octane than lower. Unless your Spree has been shaved or modified with a high compression head there's really no reason to use it.

I expect the difference in performance you noticed was coincidental and more likely caused by a dirty carb or some other issue.

[Eft37]

I filled up with 89 instead of 87 yesterday and noticed a difference in my SA50. It got to pinning the needle a bit faster, and set to vibrating my feet real hard. The noise I hear bouncing off a wall that I ride by for 1/2 a mile was different. I'll investigate further.

[Bear45-70]

higher octane won't hurt the engine. double check the compression with a compression tester. if its high,then there is a high carbon build up on the piston and head.

Actually that is not always true. It is never recommended to run higher octane than your engine needs. It can cause heating issues. It is also a waste of money on your part and is what the oil industry wants you to do. At least now there is no lead in the fuel to cause intermittent lead fouling like back in the hey day of high compression engines. An no stock scooter need anything more than the cheap stuff. Also the Big Bore guys have not prevent a single melted pistion by running the higher octane stuff.

[Bear45-70]

I filled up with 89 instead of 87 yesterday and noticed a difference in my SA50. It got to pinning the needle a bit faster, and set to vibrating my feet real hard. The noise I hear bouncing off a wall that I ride by for 1/2 a mile was different. I'll investigate further.

In your mind only. There is no way it actually did anything except cost you more money, unless you have jumped your compression to better than 9.5 to 1. It could do what you claim if the laws of physics have changed, otherwise no.

[Eft37]

The different noise and new vibration is not in my mind, though.
Causes could be: I usually add my 2 capfulls of Seafoam, some Marvel Magic Mystery Oil & a little 2-stroke oil to the tank at a fill-up. I have not yet done this.

[damalex]

you know what im goin to go try this right now on my 87 Aero my tank has vary little gas (the cheep stuff) im goin out and im goin to fill her up with the good stuff and see if i can tell any thing

[Bear45-70]

you know what im goin to go try this right now on my 87 Aero my tank has vary little gas (the cheep stuff) im goin out and im goin to fill her up with the good stuff and see if i can tell any thing

Unless you use something other than your butt to determine improvement or not, any test will be invalid.

[damalex]

it dont work at all

[patthesoundguy]

Ive been using the lower octane, 87 in my stock spree and it is totally fine. I run mine hard too, 60 to 65 miles in a trip somtimes. I only use the low octane stuff in every thing I have, never had a problem. Don't fall prey to the hype!