I bought this bike a few weeks ago and now have her running. She runs on cylinders 1-2-3 but cylinder 4 doesn’t run. I found this out by checking the exhaust on the 4th cylinder and I can rest my hand on it forever without burning it. So I removed the spark plug to see if I had spark. It sparks but seems to be doing it intermittently. Compared to cylinder 1 it seems to be not sparking at the right times. How would I fix that? Does that have something to do with timing?