I can't explain it, but my 79 Garelli Rally Sport has given me nothing but trouble since I brought it to Puerto Rico. It is in mint condition and had been in storage for 18+ years in Minnesota. It ran perfect in Minnesota when I got it running again this summer. To bring it here to Puerto Rico, I drained out all the gas and oil. When I tried to get it going after its arrival in Puerto Rico, it would barely run. I tore down the carburetor (Dellorto) and cleaned it out with Gumout and that fixed it. It ran perfect for a day or two and then the same thing happened. It started bogging down, no power. I cleaned out the carb again and it ran fine for a day. Then the same thing happened, bogged down, wouldn't rev. This time, cleaning out the carb didn't fix it completely - it got a little better but it still won't rev up to max. I'm at a loss to explain what's going on here. I read about re-jetting the carb for a leaner mixture, but I recall running it in hot, humid weather in Minnesota and never had a problem like this.
Any help would be greatly appreciated