Issue with throttle at 2.5-3krpm

[Ohioan]

I have an '82 GS 1100GL with 4-1 Vance and Hines and a stage 3 DJ kit.

The bike starts up ok, runs up through the RPMS fine. But if I cruise along in the 2.5-3k area, the bike runs rough. It spits and sputters.

When it is idleing, the exhaust pops, when I let off the throttle to slow down, it pops and cracks.

Where would be a good place start looking?

I don't know much about these Dino Jet kits, the bike is new to me.

 

[Nessism]

I suggest doing some plug chops to check the mixture. For the idle, did you adjust the pilot screws to achieve the highest idle speed?

 

[Dave8338]

Any exhaust leaks? Often causes a decel pop through the exhaust.

Otherwise lean... or valves that are WAY out of spec.

 

[TheCafeKid]

If you installed the jet kit EXACTLY as per the instructions, i found the needle to still be a bit lean exactly in the range you are talking about. You might try moving the clip to the 4th notch from the bottom, or even the third. Also, you didnt mention if you are running pods, but with the stage 3 kit, I will assume that you are?? Your idle adjustment screws will need to be more turns out than 2.5 likely. This you need to play with, and the best way is to run a temp tank on the bike, let the bike idle untill warm (might throw a box fan in front of it too, just to keep air moving around the head) and then adjust the idle screws (one at a time) by turning them out untill you hear the bikes idle rise to its highest point, and go no further. You want to go slow, maybe 1/4 turn at a time, as it will take a second for the bike to react to your adjustment. When its at the highest idle point, bring the idle back down to normal with the idle adjustment KNOB on the bottom of the carbs, and move on to the next screw. It may take a little bit, but the bike will tell you where it wants the screws if you listen. Plug chops, like Ed said, will also help to tell you exactly WHERE in the circuits you are lean, but from what it sounds like, you're lean where I was, and this is what smoothed things out for me.

 

[blowerbike]

you must have a sound stock idle circut before installing a DJ ST.3 jet kit.
anything below 4k is the idle circut.

 

[Ohioan]

I discovered that it was not a Stage 3, but a Stage 1 DynoJet kit, with 118 mains. Will this make a difference?

It has the stock airbox with a K&N filter and a Vance and hines 421.

 

[Ohioan]

I'm into the carbs now. It was still having that issue in the 3-5k range. I found a broken o-ring on the fuel adjustment screw on carb number 1 last night.

The popping and cracking stopped.

I didn't do the installation of the DJ kit.

 

[Guest]

Pull the jet needle out of the diaphram and raise the needle one notch. You do this by putting it on one notch lower towards the taper of the needle.
If this improves the problem but doesn't solve it go one more notch.

 

[Ohioan]

How do you get the needle out of the diaphram?

I'm new to all this eh.

 

[Guest]

There is a circlip way down inside the slide. I use long needle nosed pliers to get them out. Watch out because they are spring loaded.

 

[Ohioan]

Well. The needle on the first carb was set at the second slot from the top. I lowered it two notches.

What happens if the clip is too low on the needle?

 

[Guest]

Well. The needle on the first carb was set at the second slot from the top. I lowered it two notches.

What happens if the clip is too low on the needle?

It'll become richer. Were they all set the same? Are they all set the same now?

 

[Ohioan]

All four needles had the clip in the second from the top nitch. I figued as bad as the throttle response was, dropping down two notches qill help.

 

[Guest]

All four needles had the clip in the second from the top nitch. I figued as bad as the throttle response was, dropping down two notches qill help.

I agree
..............

 

[Ohioan]

I've got it up and running. It seems to be running pretty rich. I'm going to raise (toward the top of the carbs) the clip one space and see what that does. It was rich even with the fuel screws lightly seated.