sure it works .....if you need it.......but as other have said running anything more then what you need is a waste of money.....

Most ATV will run fine on 87..... if you have compression over 10:1 be safe and run 91.....

there is one secret that people don't tell you about the modern 4-strokes......and that is valve run-out that happens when the octane does not match the compression.

A lot of ATVs out there recommend 87 octane, but have compressions above 10:1 but are still recommended 87 octane..... what the manufacturers don't tell you is that 87 is not really ideal for those machines...

But here is the dirty little secret - the EPA/DEP has set standards for all vehicle manufacturers where they need to pay tax for any vehicles that require octane ratings above the US standard 87 octane. So rather then pay the tax, manufacturers recommend 87 octane, but then turn around and recommend you adjust your valves constantly..... what you are doing there is checking for the ever so slight valve run-out that slowly happens with the moderate pre-ignition you are getting by running the lower octane.

A car or lawnmower running 8.5:1 compression will run perfect forever on 87 octane, an ATV with 10.5:1 running 87 is going to need the valves adjusted constantly to make up for the run-out.

The factories make out twice on this, since they get away with saying your quad only needs 87 octane, and it gets you into the dealer for valve adjustments every spring. It is a win-win for them..... and in some ways the customers would rather pay for the cheaper 87 octane and just pay for the valve adjustments - fact is it might be wash with an honest dealer who will only adjust them when needed - and if you can adjust them yourself it might be a gain on the part of the consumer since you save the cash at the pump........

What all this means is use your own judgment...... I run 91-93 in my z400 exclusively, and I also put it in my Wife's Raptor since we use the same can....... now technically I could get away with 87 in the Raptor and probably have no issues - but if I run it in the z400 I will most certainly be adjusting the valves in 6 months. The 11.4:1 compression should have at least 91 octane to be safe - anything more like 93 is OK - but beyond that there is no point.

Once you get into the 12:1 range, you could start considering race fuel or octane booster to try at bump it to around 97 - getting into the 13:1 range and you might go even into the 102 range - I used to know an engine builder who had a chart on his wall that said what octane you needed for what compression for his customers to read. I wish I could find one I'd copy it and post it here..

 

Hotblooded I agree with you but like I said "The lowest octane you can run with out pinging" more CR will reguire more octane to stop pinging......that is kind of understood. But running 105 octane gas in a motor that will happilly run on 93 octane gas presents the same situation just at a higher "reguired" octane.

There aren't too many average riders out there that are using adjustable cdi's on thier stock motors so they can advance thier timing curves just to make the most of the excess octane in the fuel that many of them are running, mistakenly thinking that octane automatically = HP in a can.

So "generally speaking" for the average rider "The lowest octane you can run with out pinging" will bring the best bang for thier buck.

 

<div class="FTQUOTE"><begin quote>Originally posted by: ss97

But here is the dirty little secret - the EPA/DEP has set standards for all vehicle manufacturers where they need to pay tax for any vehicles that require octane ratings above the US standard 87 octane. So rather then pay the tax, manufacturers recommend 87 octane, but then turn around and recommend you adjust your valves constantly..... what you are doing there is checking for the ever so slight valve run-out that slowly happens with the moderate pre-ignition you are getting by running the lower octane. </end quote></div>

Fascinating info ss97. Makes a lot of sense. Thanks.

I run 92 octane in all my thumpers including my lawn mower. Easier to just have 1 can of gas than keep track of which gas is in which can. When all I had was 2 strokes I ran premix in my lawn mower.

 

ss97 thats pretty cool stuff makes sense too, i always use 91-93 octane in my warrior, its a high compression anyway so thats mainly why i use it i think its 10.25.1 but yea that stuff u said does make sense, i know on 2 strokes it makes a huge difference when u mix your 2stroke mix with certain gasses, i member when i had my 76 cr250 if i used 87 it would run like crap poor power and it wouldnt last long, then if i used 93 octane is was such a big difference more throttle response, more power and lasted a lil longer, but with the gas prices and stuff i kinda wanna get the premium fuels now more than ever cuz the quality of our fuel prolly has camel spit and towel head nut juice in it.