Google maximum characters robots.txt ?

[cyberdyne]

Does Google only accept a robots.txt of a certain maximum length?

I have just looked through my robots.txt as displayed by Google webmaster tools 'Crawler access' and it is cut off approximately 40% through.

My robots.txt file is just 13kb

Many thanks

[cyberdyne]

This appears to be a bug whereby the validator tool accepts the whole robots.txt contents except when secondary bots are selected from the bottom drop down menu.