79 GS1000L on the best coast

[alke46]

Hello everyone. Thanks for this great resource!
New 79 GS1000L owner here. Got a freebie from a friend. Yes, a very good friend with a heart of gold.
This bike needs some work but it rides. Biggest issue is the gas mileage is like 10-14 miles per gallon. Yes lots of power but I want to bring it to around 40mpg or better if possible. Will be looking for answers on the forums here but if you know what could cause it to be so low feel free to point me in the right direction. Thanks!

Only thing that makes sense to me is the battery in your calculator is shot. I'd like to see your actual numbers of how much gas it takes to refill the tank after xxxxx number of miles ridden.

[Guest]

Yeesh. You have me beat. I was getting like 17 MPG when I first got my 78 GS750. I don’t remember too many specifics but the carbs had massive main jets that were drilled out, the pilot fuel screws were turned out like 2 turns and valve timing was off. Those were the biggies but there were a lot of other inefficiencies that contributed to it. I ended up getting different carbs that were obviously never monkeyed with, rebuilt those and put everything back the way they were. I also did a good stage zero (points gap, timing, valve timing and clearances, carb clean and sync, new float needles and seats, new plugs, etc etc). That work got me up to upper 30s-low 40’s mpg.

[Guest]

I'll go one a ride tomorrow, empty the tank and get actual gas mileage. It rides quite smooth and has lots of power. The previous owner did mention the valve timing was adjusted, presumably to get more power out of the engine.

[Guest]

Got 23MPG on mostly highway so i guess it's not terrible. I must be much lighter on the throttle than the last owner.

[rphillips]

23 mpg on a Suzuki GS1000? No that is very terrible. I can't help with your problem, but you sure have a problem. If that much gas is going through the cylinders, your plugs have got to be black, fuzzy, & fouled