A couple of things here.
Firstly the AJAX, dont even think about it ! This was a thing that started back in the sixties specific to diesel engines. Back then it was common for diesels to glaze the bore, some genius came up with the idea of tipping ajax powder down the throat while the engine was running. It did have the effect of removing the glaze on the bores but halfed the life of the engine at the same time. There was also the idea of tipping water in the carby of a petrol engine while running to supposedly remove carbon, equally bad idea because if you tipped too much in it would bend conrods.
Now to the compression testing. There is a correct way to go about this. As Josh says the engine should be warm and have been running. You need a tester that screws into the plug thread, the ones with the rubber end that you hold are useless. In a twin cylinder bike remove the plug from the opposite cylinder, you dont have to do this but it makes it easier to kick over. Fit the tester to the cyl you are testing, hold the throttle wide open and kick the bike over as fast as you can about a dozen times. Repeat on the opposite side.
The actual reading can vary a lot but around 110 psi and above is usually fine, as Ken says its more important that both sides are close to the same. If both sides are the same but low then that indicates general wear, if there is a difference of around 15 or 20 psi then that indicates a specific problem with the low side, burnt valve etc.
At the end of the day if the motor is running well and using no or very little oil then leave well enough alone.