Because of the amount of different factors like smartphone or motorcycle we can't recommend a specific product. But in general you should think about the following accessories:
- Smartphone mounting for the handlebar
- Waterproof smartphone sleeve
- Power supply (Connection via the motorcycle battery or a powerbank)
- Touchscreen compatible gloves
- Motorcycle helmet with bluetooth headset
Please contact a retailer of your choice to get suitable accessories. Internet forums can also be very helpful.