If only 3 or four balls fell out it's absolutely 100% safe to ride. the wear may be marginally greater, but not enough to worry about.
The key issue is stability in the fork. and you can easily check. Lock the front brake and rock the bike forward and back. No play is a pass so enjoy the bike. If you have play, adjust it out, but if you can't it probably means you dropped as many as 15 or more balls, and need to deal with replacing them ASAP.
The increased wear from a few missing balls is so minor that it would only become noticeable over months or more likely years.
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FB
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Last edited by FBinNY; 04-08-11 at 08:24 AM.