Poor mileage

[Guest]

Hi everyone.

I´m riding my mostly stock 1979 550L and using an app on my phone to track my MPGs. I´m consistently getting between 22-28 MPG which seems rather low to me.

This is my first motorcycle so I don´t know much about how they should sound or run, but I do know she starts right up with full choke unless it´s below 55 degrees, which doesn´t happen too often here. Once she warms up for a couple of minutes she idles fine right around 1000 RPM. She doesn´t backfire or smoke so I´m guessing the A/F mixture isn´t too far off. I do notice a strong smell of gasoline coming from the engine or carbs once I get done riding, but no obvious leaks. Could mileage this low be due to evaporation from the carburetor bowls?

I´ve heard that if I want better gas mileage I should go to an electronic ignition system, but I´d like to figure out why I´m getting this mileage before I start
upgrading parts.

If this is indeed low MPGs where do you recommend I start looking?

[Big T]

Your milage should be double what you're getting

I'd start with where the excess gas is going

Does your oil smell like gas

[cowboyup3371]

If you are getting a strong smell of gas while riding then I can think of one of two things - you are running rich or you have a leaking fuel tank. Even with a leaking tank though you should be getting up in the 40s (mine has several pin hole leaks even after sealing it last year and I'm doing 43mpg). Have you checked your plugs recently? What maintenance have you done?

[BajaGuy]

As far as maintenance goes, I've changed the plugs (they look good now, no excessive carbon) and the valves, plus 2 or 3 oil changes. PO changed the petcock to some sort of automatic vacuum operated thing, where It doesn't need to be moved to any position any more, or at least so I was told.

I've never noticed a gasoline smell coming from the oil, just from the engine itself, not the exhaust. It is strong enough to make my pants legs smell of gasoline after an hour ride.

Something else I've noticed, which may or may not be relevant is if I don't start her up everyday, then she'll fight me. What I mean is after 2 or 3 days of not stating the engine, then it will turn over, but not start right away. A couple of times I've run down the battery completely trying to fire up the engine and have had to rely on the kick starter to get her going. Which is why I thought that maybe the gas in the bowls could be leaking or evaporating unless I keep them full everyday.

[Big T]

Did you actually removed the oil filler cap and smell the oil?

As for the "fight" try turning the fuel tap to prime for 20 or 30 seconds and see if it doesn't start up. Turn it back to Run then

VMs are known to dry out over time, but 2-3 days makes me think you're leaking somewhere.