Carb Question 81 GS-850

[81GS]

I'm working on a bike for a friend. It will start up with a little help from some starting fluid, but dies out after you try and give it some gas. I just put back the original air box with a new filter. Now it will start up and idle, but as soon as you touch the throttle it dies out. Any suggestions? He said he rebuilt the carbs a couple of years ago, but would not run right. He had on individual air pods for each carb. Wondering about the float levels??? Where should I start????

[tkent02]

Does choke on or off seem to matter?

It idles OK for a long time once you start it with starting fluid, is this correct? If so idle it long enough to warm up the engine, does it act exactly the same way when hot?

Dying with any throttle opening is somewhat normal on a cold bike, especially if the mixture screws are set too lean. If that is it there should be an improvement when it warms up. The choke is actually only an enrichment device, which only works at idle and low throttle openings, it is not working with the throttle open. So when you open the throttle the engine leans out and dies.

Have you ever had the carbs apart for cleaning?
Most likely some passages are blocked in the pilot circuit, or the pilot jets themselves. Could be somewhere else in there. Crud around the needle jet, even something blocking the main jet.
It does not really matter where it is clogged, the carbs need to come off for cleaning, you will be inspecting every jet and every passage.

[bwringer]

Start here:

http://thegsresources.com/gs_carbrebuild.htm

Don't skip anything. We mean it. Go through EVERY step carefully and thoroughly.


Don't buy carb rebuild kits -- they're crap. All you need is a set of o-rings for $15 and possibly bowl gaskets if your old ones are too nasty.

http://cycleorings.com

You can get bowl gaskets several different places. Here are a couple:

http://z1enterprises.com

http://crc2onlinecatalog.com

[81GS]

Thanks guys, Now I have a place to start. I'm going to take the carbs off tonight. I bought some carb cleaner and will let you know what happens when I get them back together and try starting the bike again.

[Larry D]

NOOoooooo !!!

Not spray carb cleaner. Get some Berryman's and dip each of them for at least 24hrs and blow them out with compressed air. Follow the tutorial to the letter !! Be careful with the posts on the floats when you're getting pins out. They tend to snap if you're to heavy handed.

After you get done with the carbs, do a valve adjustment.

[Steve]

After you get done with the carbs, do a valve adjustment.

Well, sort of. You can do cleaning on the carbs, but you are supposed to do a valve adjustment, then check ignition timing, THEN sync the carbs.


81GS, everything mentioned above is correct, except for the best place to start.

The thing you want to do absolutely first is THROW AWAY THE STARTING FLUID.

It is far too easy to get carried away with that stuff, and it can VERY easily end in disaster.

It is far better to fix the problem, not apply a Band-Aid.

.