When the bike was new I applied this https://www.theultimatefinish.co.uk/nanolex/si3d-matte-set.aspx and then use a wash from the same company. The initial application was really easy and washing is now a doddle. If your in the habit of blow drying the bike then the residue runs off really easily.
As @Towser stated...the Nanolex Matte specific products are excellent.....just be aware though if you scratch your matte finish you are essentially buggered - Nothing can be done to rectify the damage.....if you want the ULTIMATE and IMHO if you have a matte finish then you can have the parts wrapped in satin PPF ( Xpel produce this film )....but it will need to be professionally installed.
I had matte paint protection film put on mine when I had a matte bike. Always washed the paint with baby shampoo or used clear glass cleaner and a micro wipe. Still looked as new when I sold it.
I had Expel Stealth on my white Supersport and then coated that with matte Nanolex. There are also several providers of a matte shampoo, Nanolex make one... Nanolex Matte Reactivating Shampoo is designed to clean and protect matt paint finishes and matt vinyl wraps in a single easy step. While washing your car, the advanced formula forms a molecular bond with previously applied protective layers and refreshes them. Surfaces sealed with matt-specific fully synthetic last step products therefore become better protected as a result, and water beading is significantly enhanced (which aids self-cleaning via the Lotus Effect). Nanolex Matte Reactivating Shampoo also contains a high-tech rinse aid that will leave your car almost completely dry after rinsing off.
