Not running on rear cylinder
I just got a 2003 V-Star Classic that has been sitting for about 3 years. I drained the tank and the carbs, cleaned the jets, main jet and pilot jet (very clogged), replaced the fuel filter and carb seals and replaced the battery (dead). The clutch plates were locked, so we raised the rear and got the plates unstuck using the throttle and rear brake. The bike starts and runs, but only with the choke pulled for the first 3 minutes or so. If I give it much of any throttle, it stalls. After 3 min, it barely runs w/ no choke and dies w/ any throttle. The rear cylinder is barely warm, while the front cylinder is hot. Checked spark by grounding the plug on the engine - good. Also, lots of air out the plug hole, so the cylinder isn't frozen. Also, the rear carb bowl has fuel. I didn't clean the upper carbs, but looked and they appear to be rather clean. Sorry this is a long post, but it is all that I have tried -- any suggestions? Thanks much!