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1979 gs750 idles but high revs to get it moving

  • Thread starter Thread starter Chief771
  • Start date Start date
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Chief771

Guest
Good evening! I just got my carbs back in and set the fuel and air screws. It will start and idle without choking it. Problem is you have to get the rpms way up there to get it to move as it really bugs down. Do I turn the fuel screws out more?
 
Wait for Steve or some of the other carb experts to chime in, but what about jets? And intake and exhaust?

And remember, make only one carb adjustment at a time.
 
OK, you "set the air and fuel screws". To what values?

Sounds like you might be way too rich, partly because you can start without the "choke".

Any mods to the bike? Stock intake or pods? Stock exhaust or a header?

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The bike has pods. I bought it as a non runner with the pods on it. I rebuilt the carbs and cleaned all the passags. A
 
OK, you bought it as a "non-runner", it's still a "non-runner", that's not much improvement.

Still looking for answers to the rest of the questions.
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The bike has pods and I rebuilt the carb. The air and fuel screws are at about 2 1/2 turns out each carb.
 
The bike has pods and I rebuilt the carb. The air and fuel screws are at about 2 1/2 turns out each carb. Carbs were torn down and cleaned.
 
While you had the carbs apart did you make a note of what size jets (pilot & main) you have?
 
You might want to check the Newbie Mistakes thread as linked in my signature to see if anything applies.
 
Since you keep emphasizing that it has pods and don't mention anything about the exhaust, I am forced to assume that it is still stock.
If you do have non-stock exhaust, ignore the following paragraph, as it will not apply.

With pods, the fuel screws (the ones on the bottom) should be out about 7/8 turn from lightly seated. After they are set, you should not have to touch them. The general rule of thumb for the air screws is double the fuel screw setting, but I usually start with a bit less, to provide a richer mixture for easier starting. When the bike is warmed up enough to run without the "choke", adjust the idle speed to about 1100. Slowly turn the air screw on #1 out. You should hear the engine speed up just a bit as the mixture gets a little leaner, into its 'happy' zone. As you continue turning the screw out, the mixture will get too lean and the engine will start slowing down. Turn the screw back in about 1/8 turn, move to the next carb. Note that each carb may up with a slightly different setting, so don't just do one carb then set them all to that.

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I did but dont recall the sizes now. I know the idle jets I got with the carb kit were smaller then what was in the bike. I ⁸⁷.⁶ up cleaning the old ones and putting them back as the dbike wouldn't even run with the new jets. I am going to lean out the fuel and see if that makes the difference
 
The bike has hrley mufflers on it. It sounds like the baffles are
Thank you for the info!
 
I have to apologize for my repeat posts. I was half asleep when I was on here last night. To sum up the bike has Harley mufflers on it, pod filters and no air box, I have put in new carb kits as well. If I lightly seat the fuel jets then turn them out a full turn the bike wont even start.
 
Chief771 said:
To sum up the bike has Harley mufflers on it, pod filters and no air box, I have put in new carb kits as well. If I lightly seat the fuel jets then turn them out a full turn the bike wont even start.
Click to expand...

What is a "fuel jet"? Please do some research and use the proper terminology otherwise it's difficult for us to offer meaningful help. To most of us the "jets" are the main and pilot, and these are not adjustable.

Oh, and you will need a rejet for the pod air filters. I'm not a jetting guy but I do know you will have to move the main jets at least 3 steps richer for a start. Trying to tune the carbs by tweaking the pilot screws is not going to solve the problem at this point and is pretty much a waste of time. Again, read the Newbie Mistakes thread for info such as this.

http://members.dslextreme.com/users/bikecliff/

http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf
 
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