Tuning with an air/fuel meter.

[Don R]

I pulled the carb rack, dropped the bowls removed the 130 main jets and installed 120 mains. The pilot jets are 17.5 and I left them alone. I did drop the needles one notch to the second groove from the top. I used it for a parts run today and it ran fine, just a few seconds of choke and it rode great. I have a project bike to get running but I plan to test it with the air/fuel meter soon.
The 29 smoothbores that came off of this bike had some pretty big jets too, I could probably have reduced them a few more sizes. I'm used to Kiehen sizes so I have to remember it's apples and oranges.

[Don R]

After riding the bike in cold air it seems lean so I'm putting it back in the carbs as delivered configuration. I've noticed a tendency of my test rig to read rich, I'm wondering if the length and diameter of the probe cause it to run too cool to read properly.

[Don R]

After doubting the numbers of the exhaust probe, I made a section of pipe with an O2 bung and sensor to fit between the Kerker header and muffler on my GS1100. I think I'm now getting reliable information from the Autometer gauge. The jetting in the 36's as delivered was spot on.

[dgates1]

Beautiful bike!

[Don R]

Thanks, it's a nice 6 footer, I used a lot of elbow grease on it getting the aluminum and footpeg brackets presentable. The guys here helped a bit with parts for it. I'm building a CB750 engine with a billet cylinder that will cost about what this bike did.

[Don R]

I rode it tonight in cold air, it was really lean high 14, to 15's-1 at small throttle openings, I think it means the needles need to be moved back up to where they were when I got them. When I got into throttle openings where it was just running on the main jets the air fuel went to the high 12's.

[Don R]

When I was testing with the probe everything was reading rich, one day I rode with the wind behind to my left and returned with the wind to the front to my right and it was way different. I'm not sure if it was wind in the pod filters or the headwind requiring more throttle opening. It will be interesting to watch it again now that I trust the numbers.