I'm at a loss here guys tried everything won't start, KZ250 LTD

So I can't get my 1980 kz250 LTD to start I feel iv done everything a complete engine rebuild and many more things. I had it started a week ago for ten mins now it cranks but won't putter. I didn't change anything from that moment but now today iv tried a bunch. I don't have low compression it's sitting at 125psi it seems it's not getting enough gas to the piston but even when I spray gas down the cylinder it doesn't wanna fire iv checked spark iv replaced gas. Timing is perfect ignition timing seems perfect too, valve lash is set accordingly to the book. Battery is fully charged. Iv given it a couple shots of ether with no prevail it, oil levels are fine with the oil needed (10w40). It is making this weird clicking noise out the right side however. iv swapped the spark plugs iv swapped carbs iv swapped batteries. I'm probably missing a couple things here but it cranks good I'm at a loss here guys I'm attaching a YouTube short of the issue also a video of the spark. Any info helps here idk what to do from this point forward and I'm really trying. youtube.com/shorts/f_03QFtqxz0?feature=share

youtube.com/shorts/j9D_1rLqTZA?feature=share

Something is drastically wrong with the engine based on that clattering.  Time to teardown the top end and find out what's wrong.

Oh, and never crank on the engine like shown.  No good comes from that.

Top end or right side where the sound is coming from?

I did have this engine started and running and it sounded like this prior as well.

I or It maybe sounds crazy but did the e-starter turn the engine really counter clockwise (battery polarity)?

I have them hooked up to the right terminal how would this be possible? How would I know if this was what was happening?

Is that not the cam chain tensioner knocking?

The cam chain tensioner should not be knocking. If it is malfunctioning, that could account for the cam timing being off a tooth or two. 
Did you ever confirm that the carbs are getting fuel and that the fuel level is correct?

It may be time to take a couple of days away from it and then start rechecking again. Something is amiss and the only way to find it is a careful, methodical investigation of each system, assuming nothing. 

For me, it is often something embarrassingly simple. Last year, after some maintenance on my ZRX, I put it back together and it was hard to start and ran like chit. I was almost to the point of setting fire to it when I discovered that some dumazz had forgotten to reconnect the vacuum hose to the petcock.

Hopefully it is something that simple here.

Dumazz works a few days a week at my shop, too.