just a word of warning, check all the parts before you start and compare against the old ones! i ordered and fitted new carb kits for my Z900 A4, all went well after re-assembling found when the carbs were opened and closed that No. 4 was sticking. on closer inspection with the help of a mate we found that the needle in No. 4 was shorter and was sticking in the jet when closed.
here's a picture to show the difference:
the one on the left is the new one, the one on the right is the original
Phoned NRP (very helpful) sent me a replacement, NRP said it could have a faulty item or it might be a batch problem - so beware
Gary