Stalling After Throttle Blip

[Hend238]

I'm having a small issue on my 1984 750S that I'm struggling to troubleshoot. When coming to a stop after a full on run down the highway, if I blip the throttle the bike will stall or almost stall, every time. It will only happen on the first blip. If I try consecutive blips, it won't happen. Go for another good rip, come to a stop, blip the throttle - stall. Any ideas?

[mollusc]

Slightly lean mixture perhaps?

[Larry Fine]

Dirty fuel filter?

[Hend238]

Yeah I've been wondering about the mixture but I can't get past why it only happens after coming off the main jets from a long fast run. Fuel screens are clean. I cannot reproduce the stall any other time. I wish I could because this issue would be much easier to troubleshoot.

[Pete in PA]

I'll second the lean idle/off idle condition. 

Run some carb cleaner and get some E0 gas. There wasn't ethanol when this bike was new.

[mollusc]

How long ago did you last sync your carbs and adjust your mixture screws?

[Hend238]

I'm running E0 fuel and frequent tanks of Seafoam. My bike does sit idle for 5 weeks at a time and from Oct-Apr. I take every effort to preserve the fuel in the tank. Eventually I'll pull the carbs and run them through my ultrasonic cleaner, etc, etc.

I synced my carbs at the beginning of my riding season this year maybe 1500-1800 kms ago. I have a Digisync so it's set up pretty nice. I adjusted the mixture screws at the same time. The stalling issue was present before the sync and mixture screw adjustment. I was hoping that would solve the issue but no luck. Now that it's winter I'm revisiting the issue.

I'm not stressed about it but it is a slight annoyance simply because things are not 100%.

[draser]

Is your idle rpm correct, and what do the plug looks like (white, brown-ish..)?

[Hend238]

Idle is at 1000. Plugs look just about right. Maybe a touch on the light side of brown-ish.

[draser]

I'd check the vac petcock, make sure it has flow when vac changes high-low (open-closed throttle).

Do you have the stock air box?

[Hend238]

I'd check the vac petcock, make sure it has flow when vac changes high-low (open-closed throttle).

Do you have the stock air box?

Hmm. Interesting theory. Would you mind expanding on that train of thought?

The bike will idle just fine if I don't blip the throttle which I don't make a habit of doing anyway. I did it once to see how the bike would react. I've been chasing this snag since.

My air box is stock. No vacuum leaks that I can detect.