OK, I have 8,000 miles on my built d16a6, and I still have a smoking issue.
When I'm cruising along and let of the gas fully and then get back on, I
get a huge cloud of smoke out the back for a few seconds. Another thing,
after I've flogged it a bit, there is a serious stank. It's not fried
clutch, brakes, or anything I've smelled before.

I did the break in procedure, including oil changes at 500, 1000 and 3000
miles, and I have excellent power. This is most embarrassing for me, and
Hondas. Any ideas would be appreciated.

 

What color smoke is it?

 

Sorry, that would help, huh? Light blue, as far as I can tell, so I imagine it's an oil control problem somewhere...

 

either badly tuned motor (unburned fuel) or valve not seated correctlly.

 

That would be oil. and it is not good. I would have to think maybe the rings or valve seals are to blame.

 

do a compression check to be more certain