I've read some interesting stories in the British motorbike press. This company offers bags to fit your bike along with moisture monitoring and removal equipment.
https://www.autopyjama.com/permabag-engl/motorbike/. I try to follow aircraft manufacturers recommendations for storage. This is a good article on the subject:
https://www.cessnaflyer.org/mainten...g-interrupted-modern-engine-preservation.html. The key points are:
1. geographical location affects the level of storage required - moisture is the enemy,to lakes, oceans, rivers and in humid regions there's a greater need for engine preservation than those operated in arid regions.
2. Clean engine oil will provide more internal engine corrosion protection.
3. Engines with over 50 hours will have better protection because of varnish build up. If your engine is freshly rebuilt you may want to do more.
4. If you are storing the bike for over 30 days spray the cylinder with preservation oil. You can use aviation oil, but a light household petroleum oil will work, but gun oil is very close to aircraft preservation oil.
For me, I fill the gas tank to the brim with the lowest % ethanol gas I can get. This web page lists pure gas outlets around the country.
https://www.pure-gas.org/extensions/map.html. I run the engine out of gas then drain the float bowls.
WD-40 was designed to protect aerospace structures from corrosion. I never have done it but have read many others who do. I wouldn't spray it on. The applications spec sheets I have read say to use a rag to rub it on the surface.
Finally, I try to ride the bikes at least once a month. In my part of the world it is hard to do in the December to February time frame. During this time I will idle the bikes as hot as I can get them. And I use a trickle/ float charger.