Welcome maple75. If you got 2L from 45L of sap it is likely that your syrup is a little thin. The sugar content in your sap would have had to have been around 4%. That is by no means impossible, but you never know.

For this first batch I might suggest leaving the syrup in your bottles on the counter or fridge for a few days. The nitre will fall to the bottom and you can decant the clear syrup off the top and then put that in a bottle for table use. It's much easier for a first timer.

Enjoy your syrup!