Blackened Oil from Carbon/Combustion

Recently got a low-original-mile bike running and roadworthy again. The bike was not running, and far out of tune when it came to me, but perfect now.

It has not run far enough to burn/oxidize the new oil.
(in my experience, Commandos need a long run at load to get their 3 qts of oil really hot)

The fresh oil is turning black faster than I would have thought.

How damaging is blackened oil from carbon/combustion deposits?

Its an effect of the detergents keeping the carbon etc in suspension, you will just need to change the oil more often until you fix the blowby past the pistons issue that is probably causing it. I had a C15 that sent new oil black very quickly, fitted new rings and a light hone and normality returned. Or just leave it to see if the ring seal comes back in a few hundred miles.

Thanks. I will run it up a few hundred miles, see if it gets more black and then change it.