Speaking from personal experience, these bikes can sit for very long times unattended and will start right up with as little carb cleaning. My 79 sf sat in a tack room of a horse barn for 5 years covered with a thick layer of dust that the animals stirred up coming in and out. I decided one day to pull it out and start it. After hosing it off, charging the battery and adding a little gas, she fired up and off I rode. I had only one issue. The rear brake caliper was gummed up from dust and extended rest. There were at least three periods of extended inactivity over 40+ years. In 98 after being parked long enough for the carbs to completely freeze up (this time about 8 years). I went to the yamaha shop and bought some of there carb cleaning solution , recommended by the mechanic at the harley shop nextdoor, he said his shop used the yamaha product. I pulled the carbs and followed the procedure listed and again had it running. This time I took it to the harley mech, at his home, and he pulled the engine and did a complete workover of all seals and gaskets. It had dried out over the years and leaked every where. At 18k miles, he said it looked fine internally. Since that time it has again been parked for one more long period after the alternator failed, from 05 to 2018, but I had tank and carbs off this entire time. When I put in a xscharge pma and pamco EI it came to life without any problem. but the xscharge only lasted for 375 miles. I bought a used Kaw alternator and with the xscharge magnet got it back on the road. Been running ever since. I never even considered that it wouldn't start right up. The engine never failed, only peripheral equipment. I don't ride it much now but I do have a beer with it regularly and listen to it sing out there in the shop. The battery is an agm that is a bit past 5 years old but still seems to be holding up nicely. (short story long)
