you don't need to chop it to read it. but read all four. each cylinder is different. one could be fouled, the carburators could be out of sync. a jet may be clogged. etc. you want consistency on the reads as well as a proper ratio for each cylinder.
a plug chop refers to the process of installing new plugs - running the bike under load to max RPM and then shutting it off and pulling the plugs. this is the freshest reading.
Reading the plugs is just reading the plugs and you will not only get current info from it but also what your bike may have been doing in the past.
and yes you need to read all 4.
On cb750s the plug closest to the side stand usually fouls because the fuel petcock gets left open and fuel trickles into the cylinder. It is also where oil runs to if you have a bad head gasket.
yes but the thing about plug chopping is that you are actually supposed to kill the engine while pulling in the clutch at the same time so the plug being chopped isn't "blown clean" by the next compression stroke
about impossible to do on a multi..........
pretty much a procedure for singles and twins has been my experience
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