I have been reading and reading but can't seem to find anyone that has posted where they had success mounting an O2 sensor on a ZX14.

I want it after the 4-1 to get a better reading from all 4 cylinders, but have read to stay as close to the headers as possible so would like to avoid the mid-pipe.

I am not gutting my cats, there just doesn't seen to be any other reasonable places to mount one.

Ideas?

I think the cat will throw off the o2 sensor. It burns unburnt emissions. Makes more o2 than your engine combustion. That's cool you want to get into AT but for slipons, I wouldn't. Go with a map if you want. Save AT for when you get a full system.

Or get a secondary module and weld bungs to headers. Check with Dj. IDT you need to be this precise for slipons. I'm not saying slipons are shit but I don't think you really NEED a map or a tune to run a full system safely. The big gains are with boost and that's where you had better have a proper tune.

Is this the stock OEM header? If so, there's a stamped area on the right side of the collector. It's flat and at an angle. The angle is so the nose of the 02 has the ability to drip the condensation off the main part of the sensor or it will rust it out if more horizontal in position. This stamping is for the euro models that take an 02, but every pipe is stamped with that ready to go area. That too is right before the cat so there is no false reading if read after the cat.
All I did was braze the bung in place. It will never get that hot to melt the brass. Also, I had to replace the sump bolt with a phillips. The 8mm hex head just touched the wire harness body. If I drilled lower I would have missed the bolt.

I have a steel bung and plan on welding it in, so hopefully I won't have that clearance issue.

Thanks for the advice, I'll go look under the bike today!

Hub,

Is the small circular spot in this photo the one you are referring to? Seems the only logical place for one.

Pretty much. That circular crease behind it is where the cat is placed.