I have a 77 GS550 that I picked up on Craigslist, that needed some tlc. She´s all assembled, and I was finally able to get a carb rebuild kit for the mikuni carbs. I replaced all the jets, needles, screws and washers after soaking the carb bodies completely disassembled. I put her all back together, and got her synced at around 1700 rpm. She sounds GREAT at idle, better than since I got her. HOwever, she isn´t breathing very well at the mid throttle range and doesn´t like to accelerate too quickly. And she tops out at around 5000 rpm. I pulled the plugs and they are dusty black, she´s running rich. Going by th3e Clymer manual for the bike, it seems like I did the syncing properly. But how do I better adjust the carbs to remedy my current performance issues? I am no expert, I learned bike mechanics on this, but I do have prior auto experience. These mikunis have the side screws, which are turned back 1.5 turns after bottoming out. And also, the bottom factory screws, which the manual says don´t mess with, I went ahead and replaced with the kit jets, which looked identical. Without replacing the main jets, how should I adjust the other screws? What should the factory screws be set to, ideally? I can´t find any mention of them anywhere on the internet. These are the screws on the bottom, facing down, engine side. The manual refers to these as the VM22SS. I have the plastic idle screw set to idle at 1200 rpm, she gets a little rough below that.
Otherwise, the bike is sound. I spent a lof of effort on electrical issues before I even looked at the carbs. She´s a lot of fun to ride, even before the carb rebuild. It ran okay, but she wasn´t quick off the line at all, and wasn´t putting out the power everyone kept telling me I should be getting. She idles better now, but that´s about it.