Arriving ignorant, hope to learn a lot

[Maritime]

So, the GN400 from the factory had 3.60-18 on the front and 4.60-16 on the back. With available Avon Roadriders sizes, how about the 100/90-18 on the front and 130/90 V 16 RF on the rear? (Don't think I need a reinforced tire, but it was only available in these dimensions reinforced.)

As long as the tire spec is safe for the rim width these will work. Check the dual fit models. there are some that can be either a F or R and have arrows showing how to mount for when a F or R use.