I had the engine rebuilt last year and put less than 50 miles on the sled. This year I started it up for the first time and it was running rough; seemed like it was running on one cylinder. I took it back to the shop that did the rebuild. They replaced the plugs and it was running fine for about a five mile test ride. I went to start it today and same problem. I replaced the plugs again. One plug was dry and brown. The other was black and wet. The guy at the shop told me that the oil pump was replaced during the rebuild and the engine is still breaking in. The sled ran fine for about 10 miles other than a hesitation when I tried to pin it one time. The next time I pinned it, there was no hesitation. I am questioning if everything is ok and worried about taking it for a long ride. Any feedback would be appreciated. Thanks
