There are decompression valves on both cylinders. they need to be adjusted about every 7500 miles. The starter does not have enough umph to push the engine through compression stroke. If this happpens to you and you get stuck somewhere . Try this, put the bike in fourth gear. Pull on the clutch roll the bike back at a decent push ( while seated) then pop the clutch (with or without the key on. When the engine spins through , then try to fire bike up again. If it starts this is defeniatly the problem. It tells how to adjust the decomp valves in the Manual. Hope this helps.