Ok well after doing a FULL rebuild on my engine, i made the mistake of doing the valve timing wrong on the rear cylinder it was off 180 on the camshaft timing...so i fixed that issue and gave the engine a lil starting fluid through the filter pods and it fired right up idle was perfect and both cylinders firing good! I would shut it down and fire it up a few times like 5-6 times and all was good!! Had great power as well! I even rode it around the block a few times and all was good! I WAS HAPPY!! Parked it for about 40 mins and cleaned the garage, then when it came time to pull it in for the night from the driveway i had a slow crank issue and no start.. I have already replaced battery with AGM BIG CRANK 220 cca battery, new starter solenoid, cleaned and checked all grounds, even replace the main starter cable with a bigger gauge wire, took apart start switch and cleaned the spider webs out of there, and even bought a rebuild starter from a website! This is what happens while cranking..ill leave it on the battery tender plus (10 years old unit) until the red light shuts off and goes green..the voltage at the battery will be around 13 volts static (even had new battery tested and its got 214CCA's ..and when I crank the engine it'll eventually drop to a minimum 10 volts or so and the very first few cranks sound good then it starts dying down (like rumm rummm rummmm) and then it'll just get weaker and weaker with lowest voltage drop down to about 7.8 volts at the battery while cranking! Also the engine will give a loud backfire while cranking! Scares the SHI* outta me!! I have the peacock on reserve with more than half a tank of gas, new peacock as well I've tried various choke positions and still nothing..I've spent all day yesterday trying to figure this thing out i just want it to run again and i don't understand what happen from the time i parked it for about 30-40 mins! Im on the verge of taking it in to the shop but I'm hoping someone here can lead me in the right direction..i also have a hid system and voltmeter installed not sure if those item will help contribute to the slow cranking...and also does this backfiring that happing intermittently during cranking can this mess up my newly rebuild engine cause if so i don't wanna keep trying to start it until i know for sure what is going on..