So I've recently started (again) trying to chase down an issue I have with my scoot. I bought it used a while back, previous owner, and a guy at a local motorcycle shop, said that it ran great and was just looked over prior to me buying it. I paid, rode it about two miles when it died while idling at a stop light. It wouldn't start again until I let it sit for several minutes.
I continued to have that problem, only keeping it running by feathering the throttle when coming to stops. I originally thought it could be fuel delivery, so I went through the motions of ruling that out. Then after searching about and talking to people, I decided that it could be a weak spark.
I put on a different, larger carb that came with the bike, went back to the original, and back to the larger, checked the coil and plug wire and cap, checked that it was getting spark outside of the cylinder, which it does but is weak, and I know it's getting fuel by the plug being wet after turning it over a lot.
I let it sit for a while, tuned my Super nine up, then recently came back to it to try again. I started with spark again, it wasn't able to start at this point, but decided to shoot a bit of carb cleaner into the carb. Then it fired up and idled! So I'm back to fuel delivery. I put the smaller carb back in with a 17.5mm idle jet and a 50main. I can get it to start and idle and rev, but it doesn't last long under a load. It bogs out with moderate throttle use. . I've cleaned it, checked and swapped chokes, checked the filter and vacuum based petcock. All fitting are tight but it still seems as if it's got a vacuum leak with high idle or bleed over from the tiny main. Compression is good. Also, the idle speed screw usually needs to be put in almost all the way to stay idling. I've also tried to check the air fuel ratio screw with no luck.
Any ideas?
