My 83 GS, is acting funny, at high Rpm, rather 3500-4000, during Wide Open throtle the car loses power, and feels like its really leaning out badly. It doesn't happen during half throttle at high rpm, only full throttle. Also its not really noticable in 1st or 2nd just mainly 3rd and up. I was thinking either the secondaries, or fuel pump issue. i used to have mech secondaries, but they were removed for winter about 3 weeks ago, the problem arose a few days ago. Thanks in advance. ~Matt

 

Fuel delivery problem. Possibilities. Pump not adequate, regulator restricting flow, filter clogged or partially clogged, return line restrictor not in place, carb last chance filter screens clogged (theres 4 total, 2 brass screens at the banjo's, and 2 plastic cone screens under each needle seat). Tank screen clogged, or ice in the bottom of the tank.

 

I would start with replacing the fuel filter. It's high in the probable cause list and low on cost, then fuel pump and then the rest of the well enumerated items Carl gave. But yes, definitely fuel delivery problem. Had the same symptoms in mine a few weeks ago - fuel filter handled it.