Idle Adjustment knob doesn't do anything?

[Cmarino]

Hi,

Recently buyer of an '82 650GL. I just went through and swapped all the fluids, drained the carb and soaked it in Sea Foam, replaced plugs and whatnot. The bike runs good, it just has some weird tendencies. I can't get it going without choke, because it idles too low, and the idle adjustment knob doesn't change the idle at all. Even with the choke, it will occasionally die when I go from high rpms to the clutch in. I think it's just because the idle is too low though.
Anyway, am I just not spinning the knob enough? How can I increase my idle?
Thanks

[Rich82GS750TZ]

Welcome to the forum. Which carb did you drain/soak? You’ve got 4. They all need to be properly cleaned, meaning completely disassembled, separated, dipped, sprayed and blown through. There are 2 excellent CV carb cleaning tutorials on BikeCliffs website, as well as Owners manual and Factory Service manuals and many how-tos. One other great read would be the Top 10 Newbie Mistakes thread. Both are linked in my signature.

Are your valve clearances in spec? If you’re not sure, that’s a good place to start before trying to balance carbs.

It’s highly recommended or create a signature with your bike year and model as a minimum. Go to Settings, Edit Signature.

[Cmarino]

Thanks for the reply. I did drain and soak all 4 carbs overnight, and I did seem to get some junk out of there. There was a bad amount of solids in the bowls, but I think I got most of it out with the second drain. It runs well besides the idling, so I'm reluctant to having to go through and actually clean them all, but that may be what I have to do. I have no clue about the valves, so I'll check that out. But either way, shouldn't I still be able to increase the idle with the knob?

Thanks.

[Rich82GS750TZ]

Maybe. If all the passages are clean. Properly clean means a complete disassembly and dip in Carb dip. Follow the tutorial, new orings. May need float needle valve/seats. Are you running the stock airboxes and filter or pods? Any air leaks?

[Steve]

Rich has this one under control.

Yes, CLEAN carbs are critical. Simply draining them and filling the bowls with Seafoam is NOT enough. Since it is a 'new' bike to you, it is highly recommended that you catch up on ALL of the maintenance that has probably been neglected by the previous owner. A proper carb clean and refurbishment is a tedious task that will take several days, simply because you need to soak the stripped-downcarb bodies and jets overnight. If you don't feel that you are up to the task, there are a few on the forum that would do this for you, for a modest fee, of course.

Valve clearances are also critical. They are pitifully small to start with and get smaller as the miles add up. It is possible for them to wear to the point where they are not touching the valve seats, which leads to burned valves (if you are lucky) or damaging the head.

Back to your question: yes, turning the knob should adjust the idle speed, but only if you are turning the right knob. The one you need to be turning is the one that is BELOW the carbs, in between bowls 2&3. Hoping you are not turning the large knob on the cam chain tensioner. Turning that knob very far while the engine is running can easily lead to a mild disaster.

.

[Cmarino]

Thanks for the reply Steve. I'll look into cleaning the carbs. Also, I'm pretty certain I was messing with the right knob, it was the knob sticking out between the 2&3 bowl. Now for the valves... I've never messed with valves before, and is not something I'm familiar with my any means. On bike cliffs site, I found a guide to do it for the gs850. Do you know if the process is that same for my bike? Or where I can find a guide for my bike?

[Cmarino]

I just bought and installed a new oem-fitting airfilter. It was a pain to get in because my airbox cover clips both broke, but it should be good. I'll look into cleaning the carbs. Thanks

[Big T]

Thanks for the reply Steve. I'll look into cleaning the carbs. Also, I'm pretty certain I was messing with the right knob, it was the knob sticking out between the 2&3 bowl. Now for the valves... I've never messed with valves before, and is not something I'm familiar with my any means. On bike cliffs site, I found a guide to do it for the gs850. Do you know if the process is that same for my bike? Or where I can find a guide for my bike?

Yes, the procedure is the same for all the 2 valve Suzukis

[Cmarino]

Update: Dumb mistake, the adjustment knob was just unscrewed to the point where spinning it a whole rotation didn’t affect the idle. Had to spin it all the way in, dumb mistake.
I am going to do the valves though now that you all brought it up, so thanks

[Rich82GS750TZ]

Glad you figured it out. Be sure to take Steve up on the offer in his signature to email him for his valve adjustment spreadsheet. It’ll help keep your sizes organized and do the figuring for you.

[Redman]

Welcome to THeGSR.

RIch and Steve will not lead you astray.