I have ran 87 in mine from day one. Anything more is wasting your money unless you have installed a higher compression piston.

 

Yes, at higher altitudes you can run a lower octane, but I think you are pushing it at lower levels. We do most of our riding at the Oregon Dunes. We pushed the wrong button one day getting fuel, and I can tell you I can feel a night and day difference between 87 and 93 Octane in our rides. Then to top it off, we ran out of fuel the night before our last ride day, and did not want to haul the trailor into town to get fuel (fuel tanks will not fit in truck bed with cover. So we just bought some 111 race fuel, and mixed our half tanks of 93 octane. Not night and day, but an improvment at anyrate. We not always run a 50/50 mix with 93 and 110 fuels. It does cost more, and the gain is on the smaller side but they do run better, and make those hills a little nicer with the added power. We are all stock compression (for now). Maybe someone with more knowledge then me can explain it...

 

i've ran 87 in my machine all year round since day one, i've tried 91 and 93 in my machine before and I never felt a difference, personally i wouldn't waste my money

 

can you run to high of an octane. say some 110 in my stocker?

 

wen i run 87 in my stocker it bogs out on the start n in high throttle

 

ThorMX902y,

Going to lower octane fuel is like advancing your timing a few degree's.
You will have a faster combustion and a increase in vacuum signal.
Thus if your carb is not adjusted for the fuel, you will bog at low end.
Pilot screw should be turned out 4 turns from in stop.
Number 45 pilot should be used over the stock 40 if bogging still present.
The factory is not consistent with pilot screw size.
My sons 05 still had a #40 in for pilot.

87 octane has been used by many members for years.
If you use the newer Big Gun cdi or Ron Woods, then 89.
91/93 if compression is 11 to 1 and cdi.

 

2BIG2BFAST,

My understanding is this: Lower Octane increases your timing slightly while higher octane retards it. So if you run super high octane, much higher than needed then it would be very reasonable to assume you are hurting your performance as much as by retarding your timing through manual adjustment. If lowering your octane advances it (As I've heard and OMR concurred) then raising it has to retard it.

I think the reason people associate high octane with high horsepower is because performance engines are designed with higher compression or advanced timing which requires the higher octane so that the fuel doesn't pre-ignite. So people think the fuel is actually what is producing the change in performance when in reality it is the change in engine design. Now obviously there are differences in fuels, and I'm sure from one to another you can find performance differences however in overall theory it does not.

 

So..bottom line, on a stock compression motor..stock cdi, is it worth it to try 87 or 89 octane vs running 93. Is it safe and does it produce any more power??

 

87 is fine for stock compression... it will advance your timing a little, but you will have no problems. Absolutly safe for stock compression. Is it worth it.. thats up to how badly you need to save $.35 a gallon.

 

Its not about saving money, just wanting to get alittle extra power!!