quick lesson on compression ratios since from what I gather most here don't know much about it
compression is supposed to be ambient air pressure * compression ratio (more on that later). so for example at sea level a compression ratio of 10:1 would be 147 PSI. you said in your intro that you're from south texas, so figuring you're at 500 feet (14.44 PSI) with the straight plug head (11 cc) on a 66cc that's about 86 PSI, with a slant head closer to 105, with a 7cc billet head around 135, a 6cc billet head is 158, a 5.3 is 179, and anything smaller is weirdo with a race bike territory that most vendors don't sell because they know the average consumer won't know where to buy race gas and will blame it on the vendor when the detonation they didn't notice blows a hole in the piston
and then there's me, the weirdo with a race bike who knows where to get race gas. I'm running a shaved down fred head with a 4.8cc combustion chamber on a 69cc factory stroker, and since I'm at sea level I'm running a theoretical 211.68 PSI compression.
now it's time to tell you to ignore everything I said completely, because it's all used static compression ratios when dynamic is what really matters.
I assume you know what static compression ratio is, but if not it's the ratio between the volume of your cylinder and the volume of your cylinder head. dynamic compression ratio is a little more complicated, it's your static compression ratio minus the compressible fluid lost out of your ports or past your rings or head gasket if they're not sealing.
people don't realize that the reason expansion chambers work so well is because they effectively increase the dynamic compression closer to the usually very high theoretical compression through a particular RPM band by shoving what compressible fluid gets lost out the ports on the compression stroke back in.
dynamic compression ratio is always way lower than static. I would never be able to get away with my 14.4:1 compression ratio in a 4 stroke gasoline engine, 14.4:1 is on the low end of what you see in diesel engines.
the easy way to find your dynamic compression ratio is to measure your stroke minus however far the exhaust port is opened. so my actual dynamic compression ratio is around 8.95:1, which in a 4 stroke would equate to 131.6 PSI.
then after that crankcase compression throws another wrench into the system and I cannot remember how to calculate at this point because I never bother calculating dynamic compression.
now I told you all this to maybe save you a few bucks on a compression tester because in this case if it's lower than calculated it doesn't matter, it still eliminates your compression too strong for the spark theory. if your compression tests or calculates at less than 197.4 PSI then either the ignition system is actually broken or something else is wrong. you know the drill for checking the ignition, spark plug in hand with the threads touching a fin on the motor. if it doesn't light you up something is dead between the magnet and your hand.
instead of buying a compression tester right off the bat, because compression isn't your issue, buy a multimeter. as much as I like my $300 fluke, the $6 one from harbor freight does the job. they usually have a coupon for a free one with any purchase going around too. maybe you can get one when you buy the compression tester, that would work fine
