Crf450r420

I've got an aftermarket cat and my MIL will come on after a while. I've read that some people are putting two spark anti-foul adapters on it to fix it or so they say. I've looked and don't think this will fit without hitting the body of the car, also I think it's a crappy fix. I was going to take a rheostat and just feed the correct voltage to the signal wire, but I don't know what voltage would be the normal operating range. Can anyone answer this for sure or does someone have a stock car they can measure this signal?

cruzalekz

rear o2 is not afixed voltage but rather a very very slow changing one. but there is a sensor you could buy on ebay that is supposed to fool the pcm from tripping the code (cat below threshold code) i just for got what its called.