Hi,
When I got my bike it only had one key and its pretty worn. The ignition switching on is a bit of a faff sometimes requiring a bit of a key jiggle to get it to turn. Using the steering lock is a bit of a no-go, I used it once at work and it took 5 mins of jiggling/twisting/swearing to unlock it (locking it is smooth as silk though...).
I have blasted it with WD40 etc but it didn't really improve (although I didn't blast it for long...). I heard that worn keys can cause this as well, seeing as mine is fairly worn out I was going to get a new one cut.
Can you get the key code from the bike? I believe that a key cut from mine will simply replicate the worn profile and to do it properly requires the key code.