now i have no low end power!!

i re-adjusted my cam chain and have no low end power now! why? do i need to re-set timing now?
cam-chain it quite as a baby sleeping now!
bike ran good just before this little adjustment w/ good low end, but now i have little power on take-off

did i forget to do somthing else also at same time? clutch,
i only lossened the jar nut and bolt, then retightend it back up. it was rattling pretty good, but not now!
did it tighten up to much, and thats why i got no power on low end? it is the auto tensioner (pretty sure)
my bike is a 1977 kz650-b1 all stock

Before you loosened the jam nut and the tension bolt, did you set your engine to TDC? The manual says to, but I really don't know how important that is, or what happens if you don't....

Yes I would recheck the valve timing.

I would suggest going through the valve lash adjustment procedure, not because I suspect poor adjustment, but because you will have to observe valve action in relationship to crankshaft position. If everything goes by the book then you won't have to worry that your valve timing is off.

Then I would proceed to ignition timing. It could be that your loose chain was masking an igntion problem, and you're not getting proper advance off the line?

Just a guess...