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Showing results for tags 'needle shims'.
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89 Gas mileage improvement
frankd posted a topic in Venture and Venture Royale Tech Talk ('83 - '93)
Last fall, just before we went on our 4,500 mile trip out west, I changed my carb. diaphrams. The bike ran a lot smoother under load, but my gas mileage went from about 40-42 MPG overall, down to 35-38 MPG. When I was above 5000 feet, you could tell that it was rich. When I got home, I checked carb. fuel levels and all 4 were high, so I adjusted them. I had problems with the carb floats and finally changed the needles, float gaskets, and the O rings on the float bowl drain screws to cure fuel leaks that developed when they were disturbed. Now the bike ran fine, but the gas mileage didn't improve much. I still was getting just shy of 40 MPG. I decided that I wanted to adjust the slide needles to lean out the mid-throttle mixture, so I moved them into the jet by about .075". When I started it, it was too lean. Unless I opened the throttle very slow, it would die. I then moved the needles back out so that the change was .045" Now the bike ran OK in the garage so I took it for a short ride. It felt OK. Today my wife and I had a chance to take a longer ride. Before I changed the needle adjustment, you could start my bike cold without the choke unless the temperature was below 50 degrees. Today it was almost 80, and it would start without the choke, but then die. I used the choke to get moving, then I turned it off. It ran OK. On my side streets, I hardly used any throttle. When I pulled onto a 40 MPH road, I cracked the throttle in 1st, and it bogged slightly and then pulled good. After that, no problem with throttle response. The motor sounded a lot happier. I filled it with gas and drove 98.2 miles on state highways. I ran about 65 MPH, (GPS---68MPH indicated---my odometer is accurate) and I did pass some cars in 5th gear while running the speed up to 75-80 briefly. It took 2.22 gallons to fill it again, which figures out to 44.24 MPG.