I'm running 93 or 91 octane on a stock Baja X. Runs great. Elevation around 650 ft.

 

Should run even better on plain ol 87 octane.

 

Yep

 

That's good to know. I always wandered because the gas cap actually says 91 or higher. All my other quads use 87 and it would be easier to have all the same octane instead of mixed cans.

 

Make sure you get fuel with no ethanol or, if you don't have access to fuel with no ethanol, at least get a good fuel treatment like StarTron. The ethanol will quickly ruin your carburetors and fuel system, especially if you store the machine for a little while.

 

I ran 93 pump with 11.5:1 in my DS for many many years.
now with 14:1 compression I run sunoco cam2 110 octane.


its not the same for different machines - stroke length and piston speed has to do with it too, other bikes like some 450's and such can run higher compression on pump gas than the DS - its not apples to apples

 

I'm getting too much spark knock with 93 octane 110 minimizes it alot the sensor barely lights up with the 110. I suspect because of the cam's and port work, 109 Cams along with the Ron Woods Agressive timing is causing the spark knock under load.

I dind't have this issue until I got a ported head / intake, Cam's . with my 11.5:1 piston without the port work i could run 93