i bought some ceseros without center caps and didnt want to fork out the stupid prices people want for a set so i made my own and thought it might be usefull for other people.
what you need to get is some 3-5mm plastic the less brittle the better.
i used plastic plates for mine but found out they were a little to brittle but i made them work.
what you need to do is measure the diameter of inside gap, then half it to find the radius.
when you have this measurement you can make a template, remember to mark where the 13mm bolt goes to hold the centre cap in place.
then find your plastic
draw around the template you get your rough shape
cut them out
now comes the long part of filing off the edges to get a nice round even shape.
drill out the 13mm hole for the fixing bolt.
spray up and fit!
next thing to do is get some little sticker emblems off ebay for £3? and youve saved yourself £50!