inside 5 to 6 months
Let me tell you how I do it (my jet lives in the garage).
Change the engine oil and filter.
Marvel Mystery the motor before shutting off. (called fogging).
Drain the carburetor of all fuel (I have an electric fuel pump so no brainer).
Drain all the water out of the block (and exhaust if applicable).
Fill the gas tanks and add a stabilizer (I use Lucas).
Remove the battery cables and add a tender charger and check the water level (top off if needed w/distilled water).
Hit the grease zerks on the steering cable, trailer bearing Buddy's and the front pump bearing (to push out water).
Spray the tires down with Good Year tire protector (works better than No Touch IMO)
A good coat of wax.
Pull all of the seat cushions and flip them over and make sure they're dry.
Spray all the aluminum and chrome with Amsoil's MP (metal protector) Spray to keep from oxidizing, dont forget the throttle pedal, cable and Place Diverter parts.
Shove old Tee Shirts into the headers outlets (too broke to buy cozies).
I have a plastic cover that came with a new carb I bought years ago, I put that in place of the flame arrestor to keep moisture under control...
Wait for the rains to stop so I can get it back out

GT