Well when I got the bike it always had problems with running lean on the pilot circuit. Machine gun backfire slowing down, hanging idle, etc. I cleaned the carb up many times and tried different pilot jets and got a remote fuel screw and I just couldn't get it to run right down low. I ended up coming across the advice of simulating a coast enrichening event by capping off the secondary pilot air jet and was able to richen the pilot circuit up enough to get it to run pretty good. Though I still had no control over the pilot circuit, the fuel screw and pilot jet changes wouldn't do anything. However back in October I went for a quick ride and the bike was back to it's old crap of not wanting to idle. After this ride it wouldn't start anymore. Cleaning the carb would yield maybe 20 mins of running before it stopped again. I cleaned it twice and it kept having problems and decided the mid-body gasket had finally become shot for good and I needed a new carb or to replace the gasket.
So if you are running recommended pilot circuit jetting and cleaning the carb doesn't help you most likely need this gasket. Honestly the job is easy enough, the gasket is cheap. If I had to touch an FCR that was over 10 years old for any reason I'd probably just replace it for peace of mind. Having done it once I don't see it taking more than a couple hours the second time. You could screw up the job yes, but not in a way that ruins the carb. Maybe you'd have to take it apart again but whatever. The only special materials I needed were JB kwik weld for the final assembly and Gasgacinch for holding the gaskets in place during assembly. I wish I had the knowledge and experience to do a truly useful write-up about this service.
Would like to share I did get a full refund from FCR guy.
Can't say anything about the quality of his work. But if you order from him expect it to take a week for him to get back to you. I don't know if he had some kind of emergency or something but I never got any replies back since the initial one. I just decided to attempt contact daily since his initial reply and after a few days my refund showed up. But he never responded to my messages. Maybe not so polite.... I don't know. I don't like the idea of thinking someone wouldn't have a good reason for the crappy customer service. But he never did get back to me. Unless he really is a one man show rebuilding 20 carbs a day I don't see why he wouldn't have the time to answer customer emails. Whatever, I'm glad it's over.
Just put some of that refund towards a Tubliss setup for offroad riding. Some more will go to MX boots for offroading. Can't wait to tear up the trails on my mighty DRZ!