79 gs550L ?'s

[Donut]

Ok, I've had the bike for about two months now and most of that time its either been at the shop or taken apart for painting. Since I've gotten to put some miles on it now I have a few questions.

When I'm running 60mph or so, the bikes turning about 5k rpms, is that normal, It seem like I'm always changing gears. The bike accelerates good but I'm always looking for 7th gear.

My gas mileage is in the low 30's and I know it should be much higher than that.

Since I bought the bike I've had the carbs taken apart and cleaned(professionally), petcock was rebuilt, new tires, rear caliper rebuilt, oil changed...

The bike sat for a while before I got my hands on it and I realize it takes time to work problems out. Its my first bike and it just turned 12K miles, i've put about 600 highly enjoyable miles on it.

I was told to add a larger front sprocket to drop the rpm's down at highway speeds, and from reading, sync'ing the carbs may help with mileage.


Any other thoughts??

Thanks David

[gspaul]

David your useing way to much gas, post any mod's that have been done.
Yes a carb sync can make a difference, but they would have to be way out, so I think there is a combination of tuneing to be done.
Have the valves been adjusted?
Count the teeth on the front and rear sprocket and let us know.
Has the ignition timing been checked?
By the way all these thing's you can do your self if you want. one, it cost's a lot less in the long run,two you know the job has been done right, three you learn a lot, four we are here to help you.

[Donut]

The only work that I know of is what I mentioned, to me I runs good but what the hell do I know. I will count my sprocket teeth later today, I just did a search and found some good threads on sprocket sizes and the 550 bike.

I would like to do the work myself but time is a major factor im my life and the wife would rather me spend time with the fam than tinkering. I do small jobs but as far as the engine I take it to a prof.

I'll post back later

[gspaul]

The wife and bike's, not allways a good mix.......''
Your bike should be in the 50-60 mpg area, but you can check simple things like a good clean airfilter.

[Donut]

I did change the air filter, plugs when I first bought the bike. I counted the teeth and the bike has its stock 15/50. I just have a hard time believeing a tune will get me 20 more mpg. Is that possible? It seems like the bike would be running worse than it is now.

David

[gspaul]

I'm not an expert on 550 gearing, I was hopeing one of the 550 guy's would have chimed in by now, but it has been very slow on the posting's here lately I would think because of the crisis in America.
The gearing would not be to far out.
My 650 returns no less than 50mpg(imperial) so yes you are useing to much fuel.
Does the bike start easy?
Does it bog down at a certain point and at a certain amount of throttle opening?
When the bike was tuned did they do the valve clearences?
Just trying to narrow thing's down.

[Donut]

The bike was never really "tuned", basically, change the plugs, get it to start (carbs cleaned) tires,and a few things to get it on the road. Goal is to put some miles on it to see what happens.

Just now talking to a trusted friend he mentioned it could be worn out jets. Sporadic idling, running rich and eating gas, were some of his symptoms.

"""Does the bike start easy?
Does it bog down at a certain point and at a certain amount of throttle opening?
When the bike was tuned did they do the valve clearences? """"

Yes the bike starts no problem with the choke on. And Idles much higher when hot.

The only time it bogs down is when i'm in the back yard trying to hot dog it. lol.

And the valves weren't touched.

This is helping my narrow it down, you think it could be jets?

Thanks
david

[gspaul]

Sounds like you may have a combination of problems, no not the jets, that would be to easy.
The valve adjustment is the first thing you do, if they are out far enough it can have a drastic effect on fuel economy.
I would bet you have vacumn leaks between the carbs and the head,that would account for the high idle when hot.
You can check for that by spraying a water mist on the carb boot's,if you can hear missfireing you will have to replace the O ring's between the boot's and the head,and in some case's the boot's themselves leak.
I think that's given you enough to do for the moment.

[Donut]

I started the bike up, let it idle a bit and misted. Nothing happened so thats one good sign....... I believe.

I ordered a carb rebuild kit and will now figure out how to deal with the valves. Gotta read some.

Thanks
david