I have an SP-1 with about 10,000 miles that I bought used in 2005. I hadn't ridden it much in recent years, so I went through and freshened everything up. I had never had an issue with it running. Now after it heats up (10-15 minutes of riding) the idle drops and eventually stalls. When this occurs I have to pull the choke and open the throttle 1/4 to 1/2 turn while thumbing the stater to get it going.
The other day I checked and replaced coolant. Coolant is circulating fine. Then a day later figured I'd start it and make sure the fan is kicking on when supposed to. Got it up to just under 220F and the rpms slowed and eventually stalled. I pulled the choke and stated it. Just past 220F the fan kicked on and the temp dropped to 190 pretty quickly, but the bike still wasn't idling properly. So I guess coolant temp isn't the issue.
Anyone have any ideas?