we're new at this ....is there a easy way to change the main jets without taking the rubber boots off and the carb completely out... its hard to get the job done quickly between rounds...thanks for your help
No shortcuts here.... Fortunately the more you change jets, the faster you will get at it. And yes, the carbs must come out of the intake boots and air box. I had a process where I'd open the clutch cover and use that as my table to hold tools/jets. Just use a towel to cover drive belt/clutches. When done, I'd pressurize the fuel system through the gas tank filler neck so I wouldn't have to pull it over a million times while the fuel pump filled the carb bowls.
I have found it easier if you make a jet kit (thermometer/barometer, jets, screwdriver, bowl wrench/socket, plastic magnifying lens for us old farts) and keep it handy (in your pocket/pit area).
Another thing you can do is watch the weather report for the area you are racing. Not always correct, but close enough to plan ahead. Try to estimate when you will be running your heats/finals and match up against the temps in the weather forecast. Rock Maple always used the same run order for their classes, so you would have an idea if you were running sooner or later. You can always jet for the coldest part of the day and adjust if you have time.
Definitely take the belly pan off. Makes it a 10 min. job. Just check your vent lines to be sure they don't trap fuel in them from being tipped on it's side. I usually take the secondary off first because sometimes the fuel dumps into it and all over the belt. Use a 17mm with a swivel and 10" ext. and then use the jet tool that comes with the sled. Cat sells them too.
Remove the rubber air cleaner tube from the hood. Remove the Hood. Remove the plastic air box (#20 Torox). Unfasten the rubber airbox hold down and slide it foward so it clears the carbs. Our fuel lines are long enough so they don't have to be removed them from the carbs. Remove the carbs, change jets, install the carbs, slide the rubber air box foward and onto the carbs, ( check boots) hook up the hold down, install plastic airbox, install the hood and slide on the air cleaner tube. This sounds like a lot of work but we do it in under 10 minutes.