Unexpected result, or...expected???

[orojk]

I switched my '02 roadster to synthetic oil at 12k miles.

Before this, when I was using regular oil, I needed to add it at the rate of about 150-200ml / 1000 miles (which, according to the board, is normal).
Now the oil consumption seems to have stopped (or is very low) - I put another 2k on the bike and oil level is still where it was after the service.

Is it because the viscosity of the synthetic oil is more constant?

[combustor777]

I switched my '02 roadster to synthetic oil at 12k miles.

Before this, when I was using regular oil, I needed to add it at the rate of about 150-200ml / 1000 miles (which, according to the board, is normal).
Now the oil consumption seems to have stopped (or is very low) - I put another 2k on the bike and oil level is still where it was after the service.

Is it because the viscosity of the synthetic oil is more constant?

MIght just be a coincidence. Could be getting more broken in now. Were you running Xw-50 before and after?
Riding style can also affect oil consumption. I have found that if I keep the revs below 4k, there is virtually no oil consumption. When I regularly get up to 6-7k rpm, it burns about 8-12 ounces per 1,000 miles.

So the short answer is no, one oil or the other will not affect oil consumption unless you're overheating the motor or doing a lot of miles between changes with dino oil.

[sweatmark]

I switched my '02 roadster to synthetic oil at 12k miles... Now the oil consumption seems to have stopped (or is very low) - I put another 2k on the bike and oil level is still where it was after the service.

More than likely the motor's reached a good break-in condition, slowing oil usage, rather than any impact from crankcase oil choice. By the 12k service our Roadster had stopped using much oil. My Rockster is still using too much oil at 15k miles, but it's only seen mild road trip conditions and hasn't been pushed sufficiently hard... it really needs a trackday and some hard day rides to get broken in.