'97 xj long start up

[agibsonian]

I just bought a '97 xj600 that had sat for a long time but was "restored" back to riding condition. According to previous owner, every time he rode it since then, he has to let it warm up for about 10-15 minutes before riding or it was prone to stall in first gear, or with minimal throttle input. I did see this happen when I went to look at the bike. The other thing that I thought was weird was that with the choke on it would rev to about 5000 rpm and he would let it go higher before taking the choke off. The mechanic told him that this was all because of the new pins in the carburetor (or something like that) when they were cleaned out and they need to get reseated to work properly. I am going to ride it either way because it seemed fine on the road, this just doesn't seem right to me... is there something that can be done to correct this? I have read some things about syncing the carbs or possibly rejetting them but I am a novice when it comes to bikes. Any help would be appreciated, thanks!