After inflating my tyres to the pressure indicated on the servo’s air hose, I usually check the reading against a simple pencil-style pressure gauge I received free as an RACQ member.
It has the pound-force per square inch (psi) reading on two sides of the stem that juts out and kilopascals (kpa) on the other two sides.
It’s not the most accurate gauge, but it’s often better than the servo air hoses.
They are cheap at just a few dollars and only the size of a pen, so you can carry one in your jacket pocket.
You can also buy small digital tyre pressure gauges, but remember you only get what you pay for. We’ve used some el-cheapo units which are useless.
Buy a well-known and trusted brand name, like Oxford, and be prepared to pay $30 or more.
The most accurate I have used is this Rocky Creek Designs gauge which is an analogue dial on a flexible hose. It’s easy to read and shows highly accurate and detailed readings, but it’s a bit bulky to carry around on a motorbike.