Hi All,

Got my bike all stock apart from some V&H slip-ons and it ran great. I installed the CobraFi2000, a Joker Machine air intake and LAF pipes on my 72 a month or so ago. The bike seems to have been running fine and was pulling strong. In fact, it threw up another issue, that the clutch wasn't adjusted correctly as it was slipping under hard acceleration (bike is new to me)

I put the stock headers and V&H slip-ons back on so i can make some alterations to the LAF pipes, as the rear O2 sensor is in the wrong place/angle.

The bike just isn't running right under hard acceleration / WOT. It feels like its choking itself and this morning backfired under acceleration in 1st. I didn't notice this with the LAF pipes on and i don't think it was because it was so different to ride with those pipes (so loud) that i didn't notice it.

My understanding of the Cobra was, that it constantly adjusts to give you the optimum A/F ratio?

The lights on the Cobra are doing what they should, there is a solid red when the bike is running.

Any ideas?

 

OK, so i spoke to Cobra to get some understanding of the tuner and the symptoms I'm getting.

From what i now understand, the O2 sensors don't function under Wide Open Throttle. So a faulty O2 is not the issue. The lights on the controller come on, so it has power. The bike runs, so the injectors are being told to put fuel in by the tuner. They tuner only connects to the injectors and the O2 sensors, so it would appear those functions are OK.

So all in all, its kinda confusing?

Could it just be the combination of the joker (K&N) filter and the slip ons? Is the filter too free-flowing for the slightly more restricted exhaust? Seems unlikely ?

 

The symptoms your describing are similar to what mine were a month ago. Limped it over to the dealer and turns out I had a faulty O2 sensor...but you already 86'ed that possibility right?

 

after googling 86'd


Yes i think so, but only because the bike is running fine until i nail the throttle then it chokes itself.

Would it throw a check light if there was a faulty O2 sensor ?

 

I would think a bad O2 would throw a code

 

I had a similar problem. Only lost power & ran like **** on high speed full throttle runs. I finally discovered that one wire on the Cobra harness where it connects to the fuel injector was breaking loose & loosing contact. The wire had been over crimped during manufacturing process & only 2 strand held it in place. After dealing with the idiot in tech service & sending him a cell phone pic he connected me with the top guy in warranty dept who admitted they'd had a problem with this in a batch of the units. He promptly sent me a new wire harness I installed in 10 minutes & my problem was fixed. Check your wires where they were crimped by the factory for any breaking loose. My was held on by only 2 strands of wire until it finally broke off completely & died before I could get home.

 

Thanks buddy! Very help full. I'll check the wiring this weekend when i put the LAF pipes back on.