I live just north of Los Angeles and a mechanic told me that what could in part be happening is that over the years they've changed the gas (i.e. strict gas-environmental stuff in California) and that one just doesn't get as much as one used to. Maybe. But back when I got the bike in mid 2005 (used but only 19,000 miles on it and great condition), I recall needing to turn on the reserve at around 130 miles or so.

The carbs could use a bit of an adjustment but the motor is running pretty smooth. The gas lines aren't new but I see no leaks. Valves were adjusted in 2005 and I ride a (I know, kind of pathetic) 900 miles a year on average and my odo is now just a few miles over 26,000. What could be causing this? Carbs, valves or ____?

Thanks.

 

How's it run other then the drop in gas mileage? Are your riding habits and style the same? Newer gas, especially ethanol content, can contribute to poorer fuel economy but there are a lot of variables to take into consideration. I don't see that big of a drop because they changed gas. Then again I don't live in Cali so.

 

Thanks. The bike has plenty of pickup, i.e. beyond bare minimum throttle used in driving in "civilization" (I ride mostly in populated areas) it will speed up nicely. No riding habit changes, same old same old. I don't know if there's ethanol in mixes around here.

 

I would probably start by checking my plugs and air filter first then. Ethanol is just about in all gas nowadays. So, start with basic tune up.

 

One point to check is your in-tank filter screen. It has two sections - the top for when you are on main tank, and the bottom section when you go onto reserve. Because the bottom section only sucks gas when you are on reserve (about ten percent of the time), it does not clog up as fast.
When on main, the gas has to go through a screen and down the petcock tube. After 75 to 90 miles, it has sucked up enough dirt to finally shut it down. When you refill the tank, the filling action washes the screen a bit and it allows gas through again.
Next time you need to switch to reserve, stop, open the tank and check the fuel level. If it still covers the intake tube and screen completely, then your problem may be in the tank screen.