Air Fuel Ratio Gauge

[CLIFF_MK1]

I’ve had good luck tuning my motorcycle with an Air Fuel Ratio Gauge. I searched for information on installing one in my Tiger which has a 331ci bore/stroke and Edelbrock AVS2 650CFM carburetor, but no luck in finding information. So, I am sharing my install. You have 2 choices, a permanent gauge mount or a gauge you can use and remove once the tuning is done. I choose the Innovate LM-2 Basic Kit since I didn’t want to mount another gauge on my dash ($349).

First, drill a hole and weld the 02 bung on your exhaust pipe. The sensor must be installed on the top portion of the pipe. The space for the bung is not easy to find due to the lack of clearance above the tail pipe, and the sensor should be installed before the muffler and just back of the header. A good spot is just before the pipe goes through the “X” hole in the frame for the pipe to connect with the header. If you don’t want to weld a permanent bung, there is a clip available which will hold the sensor in the back opening of the tail pipe while you use the gauge; but, you may not get as good of a gas measure with the sensor at that location.

Next, install the sensor and connect the provided cable and route the cable past the transmission away from the exhaust and up the firewall. I pushed the cable through the firewall hole at the top of the left drivers side and into the car. I mounted the gauge on the passenger side windshield with the power cable inserted into the cigaret lighter. The windshield mount is available from Innovate or from other web sites. It’s important to pull the cable out of the cigaret lighter when the ignition is turned off, and it’s not a good idea to leave the sensor installed if power is not sent to the gauge (running car with gauge off-ruins the sensor).

My exhaust system is custom 2 1/4" and comes off the car in one piece so the entire system came out to weld the bung for the sensor. To get a nice weld, I took it to a muffler shop with “30 years” experience. Well, as you can see, I could have done a better job with my stick Harbor Freight welder. Oh, well, it doesn’t leak. Here are the pictures. Now I am ready to tune. Cliff

 

[Michael]

Very detailed install. By the time you went to that extend I might have chosen to go feedback fuel injection and left it in, but looking at the underside of your car I believe you thought it through and did it exactly like you want it. Thanks for sharing.

 

[CLIFF_MK1]

Well, the advantage of fuel injection is that they tune themselves. But, carburetors are still here, and once they are tuned properly, perform as well if not better than EFI (inspite of emissions,fuel economy, etc.). The problem is tuning, and the choices are use of dynomometer, driving at different speeds for effect and/or spark plug reads, or a combination. Or, using an A/F gauge. I am obviously not an expert, but I have found the air fuel ratio gauge to really help so that's why I did this. After all the work though, I may be sorry I didn't use a permanent gauge. The Tiger dash is beautiful as it is and non stock gauges distract from what's there. Some owners have put gauges behind a door on the glove box, which is cool, but then you have no glove box. Cliff

 

[Michael]

Ages ago I did seminars trying to help old school mechanics understand fuel injection and computer controls (so they'd buy our parts). I enjoy carbs and it is astonishing how well they work when properly tuned; in drag races they can match or beat aftermarket fuel injection systems. A really good feedback FI system would probably give better overall drivability, especially if conditions vary. Not many of us use our toys as daily drivers, so it comes down to personal preference. Mine is a simple carb set up, tuned by feel.

I respect other choices, and I really respect the attention to detail shown in your pictures.