Hesitation from idle

[Skinner]

1981 GS650GL, stock. Carbs stripped, dipped and synced. Mixture screws adjusted using a Colorsync.

The bike generally runs well, I'm just fine tuning. When it's warmed up and I'm sitting at a stop light, if I blip the throttle the idle will drop down to the point where it seems like it wants to stall. I have to blip it again to bring the idle back up to normal (1100-1200 rpm). Also, when I accelerate from a stop there is a slight hesitation before it accelerates normally. This also occurs only when the bike is warm. There is no hesitation at all when I accelerate while already moving. Any ideas?

Cheers!
K

[78550GS]

Location of the clip on the needles?

[Skinner]

Location of the clip on the needles?

Whatever is stock - I didn't touch the clips.

[tom203]

Back out mixture screws another half turn or so.

[Steve]

Clips are not adjustable on those carbs, and with everything stock, shouldn't need to be changed, anyway.

I agree on backing out the mixture screws, but maybe only 1/4 turn first, to see if that helps. If not, go the other 1/4 as well.

.

[Larry D]

Back out mixture screws another half turn or so.

I disagree. Sounds to me like he is slightly rich, so, turning the screws out will only make the mixture more rich. I would recommend turning the screws in a quarter turn, which will lean out the mixture slightly and reduce the bogging idle. Just do quarter turns until it accelerates properly. I used to carry a small screwdriver with me for several rides and adjust them as needed.

[Skinner]

Okay, we have two different opinions here - either I'm rich or I'm lean. Well personally, I'm neither rich nor lean, but I digress. :-)

The Colortune works for me (obvious color changes) and the mixture screws are adjusted to produce a nice blue color. I did go to both extremes when adjusting so I could see the difference between a too rich mixture and a too lean. Having said that, I know there's a wide range of adjustment where the color stays the proper blue. I just mentioned that to let you know that I should be in the ballpark adjustment wise. So, I'll try enriching it a bit, and if that doesn't work, I'll go the other way. I'm just curious as to the logic behind each opinion - enlighten me?

Cheers!
K

[tom203]

I'm guessing that colortune left him lean at idle , but try both directions!

[dago]

if the revs hang up when throttle bliped it's lean, if the revs drop it's rich