Quick diagnosis confirmation - carb/fuel issue?

puftas

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Been getting my 77d on the road again, after 2 years of sitting and me replacing most of the electric system. And I should probably have given my tank at least a good rinse before using. She's riding, I've been out on her the last 2 weeks, but she's been gradually running worse.

Symptoms:
  • Runs fine intermittently, and when I first had her out.
  • Now worsening loss of engine power when I throttle on.
  • seems to be in only first 1/4 of throttle, so I'm assuming pilot circuit is the issue
  • Sometimes I go and start her, and for a few minutes she runs fine.
  • Then the power loss starts in again.
  • Seems to be slightly worse when I'm in gear, clutch engaged vs neutral. But my gears normally drag a little.
  • makes what I would call a PUTT-PUTT PUTTERING sound as you roll on, and doesn't grab like she should
  • sort of a low burbling that shouldn't be there. Normally she sounds more like a sewing machine
This is the pilot circuit yes?
  • gas vent should be good.
  • need to check my inline filters, but I think they're flowing okay.
  • charging/battery/electric all seems to be great (thank Hugh for PMAs)
Just wanted to check with others that I've read the symptoms correctly, before I do another carb-clean. Starting to get a little more confident in my diagnosing skills, and damn that saves a lot of needless wrenching.
Tank is not bad at all. More varnish than rust. But prolly enough to plug the pilot. Now just gotta figure a way to clean my it out in an NYC apartment or on the street... :umm:
 

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The "putt-putt-puttering" when you roll on really sounds like one cylinder dropping out, possible float level. Floats started leakin? Needle valve leakin?
 
UPDATE: popped the carbs off, found some metal in the mix tube. like shavings from a stripped thread. no idea where that's from. I think she was losing a cylinder when I rolled on, but she's running now, and not bogging anymore. All good, and on to the next things to fix.
 
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