sugino 400 crank caps tap size

[dj B silverlite]

Ive been doing some digging and found my 400's so I put them on my quad but I cant get the caps to fit. ive had them rechromed a while ago amd think maybe the threads need retapping. They look ok though to be fair so not sure. Does anyone know the tpi size so I can get a tap?
thanks in advance 

[mattbloke]

If you have a crank removal tool try giving that a run in to clean it up perhaps?

[dj B silverlite]

I havnt got one but I could do with one. I never thought of that   ill try that first see how I get on. cheers