My 2000 Trail boss 325 was still a running bike but had a major knock after blowing a oil cooler line so I purchased another used engine that had been in a rusted out frame so I changed the engines only to lose spark after the installation, have swapped out the coil and swapped out the CDI and still no spark. I should also say both bikes were runners at the beginning of this engine swap, what am I missing?, thank you in advance for any help.