If I set my timing using the yz timing specs the punch cog on the backside of the intake is slightly below the head but the exhaust punch cog is one link above the head. That is setting the top cogs 12 pins apart. Does this seem correct. If I change it to 13 pins apart on the top cog the intake is still slightly below the head and the exhaust changes to slightly above the head. I set it up for 13 pins apart and tried to fire it up but it backfires when I kick it. At one point it did fire up and run for about 30 seconds and that was the only time it started. Help Help!!