Picked up this 1980. Runs great and got up to speed which was 27-29 mph with me on it @ 250 lbs. There was couple issues; one being problem with fuel leaking from gauge area, and the carb was leaking some fuel as well.
So took apart carb. Cleaned it, put it all back together. Took the gauges off of the tanks and capped them off where the gauges were. Have not touched any of the oil whatsoever on this thing. It has the proper 500 mil and it was fresh oil. So left it alone.
Now that this was all done the bike will only hit 19-20 mph. It idles great. It starts first kick even after week sitting and extreme cold weather. I mean the bike just starts up runs great. Doesn’t cut out nothin. Any ideas on what this can be? Going from stock speed to losing 8-9 mph just with carb pulled off and cleaned, and the only other thing changed was plugging the gas tank where the gauge use to be.