Buckeye you only have to put 1 quart jar of gas in 5 gallons of racefuel with the 927 to keep it mixed. I thought you only had to  worry about it when its cold. I ride around 3,700 feet above sea level and never had any problems with the castor.Mix you up a gallon pour enough in a quart jar and  let it sit for awhile and see how well it stay mixed. But dont mess with the jar to shake it back up. Just to test to see how it does. But you would have to worry about it in the winter. But i havent had any problems or you can use Maxxis  hi test octange booster with castor to keep it mixed. I would findout you octange level need for you motor after it finshed. You dont want to burn a hole in the new piston from not having enough octange in your Zilla.