Lean or rich-dumb question

[PAULYBOY]

I've seen people mention in several threads adjusting the mixture screws and they refer to it both ways, wherein some people say screwing them out leans the mixture and some say screwing them in leans it. On an 81 850, which is it? Does screwingit out (counterclockwise) make the mixture leaner?

[Dave8338]

I've seen people mention in several threads adjusting the mixture screws and they refer to it both ways, wherein some people say screwing them out leans the mixture and some say screwing them in leans it. On an 81 850, which is it? Does screwingit out (counterclockwise) make the mixture leaner?

VM vs. CV carbs...81 850 out richens.

[PAULYBOY]

The CV carbs are the newer kind, right?

[BassCliff]

On an 81 850,... Does screwing it out (counterclockwise) make the mixture leaner?

No.

For that year and that model bike (w/CV carbs), turning the mixture screw counterclockwise makes it richer.


Thank you for your indulgence,

BassCliff

[BassCliff]

The CV carbs are the newer kind, right?

Yes.

TYFYI,

BassCliff

[Nessism]

No.

For that year and that model bike (w/CV carbs), turning the mixture screw counterclockwise makes it richer.


Thank you for your indulgence,

BassCliff

Cliff's the man. Do you have a tutorial on how to adjust the mixture screws yet?

[Steve]

The easy part of tuning carbs is remembering that turning a screw OUT or LEFT increases something, and turning it IN or RIGHT will decrease that something.

The hard part is remembering what that screw controls.


On the early ('79 and older) GSs with VM-series carbs, there is a fuel screw on the bottom and an air screw on the side.
You need to adjust the fuel screw to get enough gas in the idle ports, then adjust the air screw to chage the air/fuel ratio of the mixture.

On the later ('80 and newer) GSs with BS-series carbs, there is a single screw on the top of the carb outlet that controls the amount of a preset mixture.
The mixture is preset with the combination of the pilot air jet in the carb intake throat and the pilot fuel jet that sits near the main jet, under a rubber plug.

.

[BassCliff]

Cliff's the man. Do you have a tutorial on how to adjust the mixture screws yet?

Hi Mr. Nessism,

Here's the collection of carb wisdom many have shared and I have saved on my site:

Plug Chops-Highest RPM Methods
(by Mr. tkent02 and Mr. psyguy)

Carb Specs-Float Height-Jetting

Carb Bench Sync Notes

More Carb Stuff

Mikuni BS32SS Carb Manual

Mikuni VM/Smooth Bore Manual

But there is no real, step-by-step, overall, concise "how to" for carb adjustment. I'm a little weak on carbs, hence my collection efforts.

Thank you for your indulgence,

BassCliff

[PAULYBOY]

Thanks, guys. I read most of the tutorials with interest. Last week I screwed my screws out 1 more full turn because I thought it was a bit rich, not like I'm really experienced with this stuff. So, today at lunch, I'll try to turn them in using the smallest driver possible since I can't really take the tank off at work. In means lean, out means rich.

[doctorgonzo]

Thanks, guys. I read most of the tutorials with interest. Last week I screwed my screws out 1 more full turn because I thought it was a bit rich, not like I'm really experienced with this stuff. So, today at lunch, I'll try to turn them in using the smallest driver possible since I can't really take the tank off at work. In means lean, out means rich.

Unbolt the tank under the seat, lift it up (it will go pretty far depending on length of gas and vac lines), and stick a towel, rags rolled up, a beer coozy, anything under there and prop it up. Most carb things can be done like this instead of pulling the tank all the way off.

[PAULYBOY]

Once again-in the words of the cartoon beer guy-"GENIUS!"
Since I had to use a foot of fuel line for my backward facing, wrong year, bike bandit petcock, that should be pretty ez.

[doctorgonzo]

Once again-in the words of the cartoon beer guy-"GENIUS!"
Since I had to use a foot of fuel line for my backward facing, wrong year, bike bandit petcock, that should be pretty ez.

I have the same petcock, but got it from Z1.

[PAULYBOY]

it's really my fault cuz I thought I had an 82. NOT!