Unless someone has done 875 oil pump rebuilds -
I would narrow down the oop’s to that. 

You were bleeding profusely and you removed the .45 ACP bullet yourself with vinegar and a paper towel. That is/was your NEW NOISE.

So, someone must call DEET in an emergency especially after a complete new top end….

I have two bikes giving me problems, instead of dealing with things above my skill set - I’m sanding a aluminum fender in my sink… 
I do know my limitations…. Indubitably…..

a negative ….

I wouldn't waste my time with anything more than:

Put it back together.

Clean and oil the air filter

RIDE AND ENJOY!

I agree 100% with MarkT enjoy your ride

+1 on MarkTs advice to RIDE AND ENJOY.

I have a small herd of bikes that have never had their tops popped for inspection, and I have been riding them season after season.

if there was a bit of grit from machine shop that's probably gone by now. I agree with washing out airbox, oiling filter and riding it! Love to hear it run

Personally, unless it is rattling away or showing signs of low compression I would not be too concerned. Absolutely perfect bores are a rare thing.

My 79 DT was slightly worse than that and I was just going to bang the honer down it. Until I removed the jug and had a closer look... And the full horror of the machine shop came to light.

If it is grit, the piston will also be scored and may have chunks stuck in the alloy skirt that can be felt standing proud of the surface at the top or bottom of a score.

If the piston is not scored, then it may be that you can give it a hone and fit new rings, checking the gaps carefully. That is if it bothers you.
I have always been an advocate of letting it develop until the cause is unmistakeable.

Newly rebored air coolled bikes do make a variety of noises, ticking usually because the ports have not been chamfered and more usually a "shooshing" noise on tickover as the hone marks and rings grind each other together as they bed in. I always put that down to ring resonance getting amplified by the fins.

If it is not clattering away like a marble in a coffee can, I would just whistle cheerfully and screw the lid back on.

I got everything back together today and cleaned the air-box and filter and re-oiled the filter.

here is a link to the bike running two minutes after I started it cold:




This is a link to a video after a 20 minute ride.




I don't think what the howl I hear is discernible but it's worth trying.

Thanks again.

I put my foot on the heat shield to prevent it from rattling . I somehow cracked the top and bottom.

I think is sounds fine.  
 enjoy your bike. I would let you hear my CT1C but it’s a piston port so it sounds different 

She's good. Has a bit of piston rattle [racing clearance] & exhaust resonation through the walls. Don't think you lifted the cylinder to [measure skirt clearance?]. Just a question. Oil union & hollow bolt at the cylinder looks different to an original [or just my eyes?]. Bike looks good--go ride & enjoy.