Join Date: Dec 2013
Location: Mexico City
Motorcycle: GSX S750, D675R, Versys 650
Re: 93 GSX-R750 - Cylinder 3 Not Firing
Uhm, no; its not the header. It will idle without the header, so no.
Try swaping the coils first just to double check it's not a coil problem. IIRC those were waste spark systems, two cylinders connected to the same coil; swap the wires on the other cylinder that shares the coil with No. 3. (it's cyliner No. 2). I think based on the fact cylinder No. 2 works fine that the coil is working, but the cable might be shot. If the problem doesn't move to cylinder No. 2 that would indicate the cable and coil are fine; spray starting fluid directly on carb No. 3, if it fires that would confirm there is a problem with the carb, if it doesn't then you'll need a compression tester to figure out if it has enough compression.