Those old pumps really varied on how long they would last. I went through 4 pumps, now before you say what the hell. I had over 100,000 miles in the first 4 years of the bike. Even drove nearly 300 miles in a day through the hot summer day out west to reach a dealer for a new pump. Had called the dealer and they even told me ride it like normal, remember it was originally an air cooled motor and will survive. The water pump is just supplemental cooling of the heads.
Now once you do get the new upgraded pump system, based on the M8 motor, it works fine. Most recent pump has been in for 2 years and 50,000 miles. I now have 180,000 miles on the bike and it is running strong.
Bill