How do I adjust my mixture??

[defwack]

I realize this is probably a pretty noob question to ask, but hey... better safe than sorry.

I have an '80 GS850L, and I just want to adjust the mixture as it seems to be running rich (soot on the sparks).

Thanks

[defwack]

Also, any idea on what the gap should be for this bike, or is that a plug-specific thing?

[rgierer]

I believe the 80 has the CV carbs. There is only one adjustment on the CV and if I rememebr correctly it was factory sealed and plugs needed to be drilled out to adjust.

As I recall they are on the top of the carb toward the engine side and you pretty much have to have the tank off to adjust them.

Douglas Adams?

[defwack]

Interesting... I was going to guess that it was the little knob that's sort of under the carbs (in the pic attached)... what then is that thing?

And yes, it is Adams... from the lesser-known Dirk Gently's Holistic Detective Agency book. Nice guess!

[defwack]

oops... forgot the photo... what is this thing???

[carlosjc401]

oops... forgot the photo... what is this thing???

Hey the knob in the photo is a the Auto chain tension. Don’t mess with it unless you are going to take it off and then only if you know what you are doing

[defwack]

... and I do not know what I'm doing, so it will stay untouched!

Thanks for the info. As for the mixture, what you're saying is that it's pretty major surgery to adjust the mixture? Is it worth it to do the job (or, more likely, have it done for me), or can I just leave it as it is (rich) without worrying too much?

[Scud]

When was the last time you changed the air filter?? This can cause a rich running bike and plugs. It more then likely can be cured from other problems being fixed first, you should not have to drill out the mixture screws if you ask me, ot least make that the last straw.

Scud

[defwack]

That's potentially good news, since I wouldn't even know where to begin with the drilling part. I don't actually know when the air filter was changed last, because I just bought the bike used a few weeks ago. I'll try changing that first before I go boring holes in anything.

Thanks!

[DaveDanger]

defwack, I'm in the process of fooling with those self-same mixture screws on my 81 GS850 this minute. The thin sheet metal plugs had been previously drilled out on mine and some effort has been expended on adjusting them. The way I understand it, unless they've ever been drilled out and fooled with, they are almost always set too lean. It was an EPA thing to try and meet emissions controls in the 70's & 80's. If you're pretty sure you're rich, check out and make sure your choke isn't misadjusted and causing an overly rich mixture even when it's turned off. or like previously suggested, make sure the air filter isn't clogged limiting the amount of fresh air flowing.
As for D. Adams... I have the collection I re-read them when real life becomes unbearable.

[defwack]

More good (non-drilling) ideas! I like! I will definately look into the choke cable possibility as well, since I know that there have been other 'cable' issues with the bike. The throttle cable is having some difficulty at the moment. It functions mostly-normally, except that it throttles-down when I turn left, and throttles-up when I turn right. Not a lot, but enough to be noticeable and warrant attention. I've pretty much mastered compensating for it with the throttle, but I think I'm going to replace that cable while I'm in there.

Adams' works are the only books I've ever re-read after the first time around. Not just once or twice either, but on the order of several dozen times over the years since I discovered his stuff in 9th grade.

[Ghostgs1]

Hi defwack, Out of curiosity, how clean are your carbs? If the floats are sticky they will make the mixture rich. You may want to run some BG 44K thru them with your next fill up. That stuff is real good. Ray

[defwack]

Good question... I don't know how clean the carbs are. Like I said, I just got the thing a few weeks ago. Is there an easy way to check this? I'll get some of that stuff anyways, as it's probably part of the problem anyways, instead of just one issue. Thanks!