Idle help please - 79 GS1000L

[Guest]

I used a Colortune and found that cyliners 2 & 4 we quite rich at a faster idle between 1500 and 2000.

So, I adjusted those carbs using the synch screws on top of each to get to the desired blue flame. That immediately made the bike idle much faster -- racing idle. Problem is that using the idle screw I cannot decrease the idle below 1500.

Bike seems more lively and does not hesitate anywhere from off idle to 9000 rpm, but I do not want it racing in neutral or with the clutch pulled in and I do not want to engage 1st gear from neutral with such a high idle.

What did I do wrong?

Thanks in advance.

[Seana23]

Hi babes.
Thats odd. I wonder if either the cable is too short or if something is fouling the round thing that the cable joins onto, down on the carbs?
Or maybe its routed in a strange way, pulling the cable too tight.
Could it be that you have a single throttle cable but its joined onto the throttle at the handlebars by the wrong hole?
Just a thought.
Xxx

[Steve]

I used a Colortune and found that cyliners 2 & 4 we quite rich at a faster idle between 1500 and 2000.

So, I adjusted those carbs using the synch screws on top of each to get to the desired blue flame. That immediately made the bike idle much faster -- racing idle. Problem is that using the idle screw I cannot decrease the idle below 1500.

Bike seems more lively and does not hesitate anywhere from off idle to 9000 rpm, but I do not want it racing in neutral or with the clutch pulled in and I do not want to engage 1st gear from neutral with such a high idle.

What did I do wrong?

Thanks in advance.

What you did wrong is quite easy. You used the wrong adjustment to tune your bike.

You are using a Colortune to adjust your mixture, so you need to adjust your MIXTURE screws. The fuel screws are on the bottom and don't generally get played with. The AIR screws are the ones on the sides, and are what you need to adjust for proper color in the Colortune. By the way, this should be done at, or near, idle, not between 1500 and 2000.


The synch screws (yes, you called them that, too) are there to synchronize the opening of the four carburettors. To do that properly, you should be using the Colortune's brother (or is that cousin?), the Carbtune.

.

[sedelen]

Hopefully you'll be able to increase the slack in your cable at places where the cable can be adjusted, that might allow the idle screw to have more adjustment.

[Big T]

What you did by tweaking the sync screws was set your carbs slides so high they can't go back down

Go back and sync your carbs at a lower level on the sync tool, that will bring the idle down.

Then, go tweak the mixture

[tpalmer1359]

Thank you very much Big T & Steve. Just what I was looking for.