I have a 93 300ex with 96 wiring harness. It starts up fine but after you rev it up past half throttle, it cuts out and bogs but then gets back to idle. The idle adjustment screw is not touching the throttle guide. The floats are good and there is no big kink from tank to carb. The carb is getting plenty of fuel. dk why it won't rev up please help!

 

The most likely cause is a partly blocked main jet. Check the plug colour, black and sooty and it is getting too much fuel, due to choke sticking or blocked air filter. White plug nose and it is getting too little fuel, blocked jet. Change the plug anyway, another possibility is the spark cutting at higher revs, this also gives a sooty plug. The cause of this can be anything in the ignition system, or even an overcharging voltage reg, but the first thing to change is the plug.

 

Sounds like the Carburetor, possibly bad gas or a clogged filter but I would think carburetor.

I would rebuild the carburetor .

Buy one of the cheap Chinese carbs and use the internal jets or purchase a carb kit.

Both work and its an easy job.