I think a compression tester is over rated and not essential. I can think of other areas to spend money. I have one but might use it once a year and only on multi cylinder 4t bikes when looking for a 'weak' cylinder. Basically its either got compression and running fine or it has not got got compression and running poor. Usually you will see it leaking at the head gasket or feel lack of compression with thumb over plug hole and if its rings, it would be smokey or feel weak when you kick it over. Plus if you are doing a resto and want reliabilty at the races you should be taking the top end off and measuring piston/bore/ring gap/checking valves etc any way so you will pick up anything out of spec there anyway so no real need for a compression tester i think. Spend your money on good spanners, sockets, screw drivers, impact driver & bits, multi meter, micrometer, calipers, bearing pullers, drifts etc. Often the best tools are home made one too.
