I’m going to put number boards on my KTM, and wondered about putting a number on them. I’ve hear with cars, if you have number boards with numbers on it invalidates your insurance, is that true and is it the same for bikes?
speak to your insurance company, its not an offence ( ltd edition GSX-R Sheene rep ) to have numbers…but you have to prove yoy aint racing it…like the number plate, headlight is not a clue huh 
How many bikes have ‘46’ on them?
Insurance companies state that anything changed from OEM standard specification needs to be adjusted to your policy if not stated already… It IS classed as a modification therefore you MUST notify your insurance company otherwise your insurance could be invalid. Although some people do not bother with this as your premium is more than likely to go up but if you have a bad crash or injury is inflicted upon someone other than youself, your in big trouble as your theorectically not insured.
IMO number boards isn’t much of a modification because its only graphics and may not cost as much to change the policy in question, where as something like an aftermarket exhaust may cost quite a lot as it increases BHP and soforth. Some companies may not even charge you, it’s worth asking about it, rather than your insurance bein void!
-Hennessy