Ignition or carb trouble on GS1100

[oregonjake]

Okay, my new 1983 GS1100E and I just got back from her first 75 mile shakedown ride. Here is what I noticed, and am not sure if it is ignition/electrical or fuel/carb so will post this same question in the carb forum. If I roll the throttle on smoothly, she accelerates like a liter bike should, up to about 5Krpm, then it feels like either one or two cylinders quit sparking OR one or more carbs ran out of fuel. If I smack the throttle open she immediately shows the same symptoms IF I am between 4 and 5Krpm, at lower rpm she takes right off. I am trying to use my vast but aged memory to think where I should start, my first thought is ignition. I don't want to pull the carbs just yet, hopefully it will be just a minor hiccup and not a massive undertaking. The bike has a tach that is wired to the ignition, and the needle starts fluctuating between 3500 and 4000rpm, never going above 5K. Could the tach be wired wrong as to cause the ignition to malfunction, or should I look at another component? Could the float levels be too low as to cause fuel starvation when I crack the throttle? Thanks in advance for the advice.

[phydeauxmutt]

Even though the bike is "new" to you, it's still 33 years old and is probably missing out on about 30 years worth of maintenance.

In no particular order:
Adjust the valves
Clean the carbs
Clean ALL the electrical connections
Verify new-ish tires and brakes
Replace all fluids

Do you have any idea how long it has been since the bike has seen some regular use?

[oregonjake]

Well, allegedly the kid I bought it from claims he went through the carbs and adjusted the valves. The valves sound fine, no unwanted clatter but the idle is a bit rough and when I brought her home last night and warmed her up the idle stayed at about 2K. I tried turning the idle screw down and made a little progress but it is tight enough that I believe the carbs were not taken off and cleaned. The kid said he rode it semi-regularly (huh?) and it was warm when I got it in Portland but I only rode it around the block as it was pouring rain. I know, never buy a vehicle at night or in the rain, but did I listen to my mother? No!

Oh, brakes, A bit spongy, the kid said he replaced brake pads but I think bleeding will help.

[JJ]

Rule one. Never believe what the seller tells you.

[Rob S.]

I insisted the engine was cold to the touch before he started it for me.