84 650 boggs at 1/2 throttle

[danmurphymn]

I got my 84 650 in late spring this year. I had to ride it home on choke because that is the only way it ran.  I have since cleaned the carbs, twice.  Replaced the plugs, wires, air filter and oil / filter.  It rides fine, no issues until 1/2 throttle or so, it boggs down.  It seems to get better as it gets warmer but it is still there, I'd like to see how fast my bike really is.  Any ideas?  I disassembled the carbs when I cleaned them but didn't take them off of the rail.  I've ran about 2-3 cans of sea foam through the tank, 1/2 can at a time.  This seems to make it a little better, but it could be in my head.  Also it seems like it possibly runs better when I use 87 or 89 octane.. Whichever is mid grade.  I'd appreciate input, or better yet a magical answer that requires little to no work... 

[daclown]

Seems like a stupid question, but are the carbs in sync?

[gammer]

Carb sync always helps, but its the last thing you do when you are done all the work and the bike is pretty much running correctly.

Is it falling flat at mid range or 'bubbly'/rough running?
Flat means its not getting enough gas...could be from lean jetting, aftermarket exhaust and/or aftermarket air filter (removing the air box lid, holes in the air box). It could also mean a fuel delivery problem, like a bad pet-cock.
Bubbly would mean its running rich and getting too much fuel. Again, incorrect jetting, dirty air filter, stuck float.

[martian]

Check the diaphragms very carefully.  Any holes rips or tears will severely impact performance.  You also need to make sure the slides are very clean.  Gummed up slides can cause them not to open all the way and cause the symptoms you are having.

[ROJ]

Don't forget to examine the air cut-off diaphram on the sides of the carbs. You can only reach the one on the far left carb without taking the carbs fully apart. The condition of that one will generally tell you the condition of them all, so if it looks OK then the rest likely are as well.

[JordanA]

Air cut-off diaphrams?  Are these visible while on the bike (well, at least the one you're saying on the far left)?

[ROJ]

They look like this.. when on the side of the carbs. Some may differ and I'm now unsure as to where they are on the 650 carbs.

[thomas.clark]

does it run better when the gas tank is full, or when you've just opened the tank?  could be getting a vacuum and starving the engine under open throttle.

[flynrider]

  It does sound like a fuel starvation problem.  Since you've been through the carbs twice, start looking upstream.  If the bike was sitting long enough to get the carbs gooped up, you may have a similar condition going on in the fuel tank petcock.   Pull it out and clean all of the screens. 

[cjbear11]

There are no air cut-off diaphragms on the 84 650 carbs. They changed from 82 to 83.   

I know you said you cleaned the carbs, but when you did, where the jets also cleaned? There are tiny little holes that go up the jets that allow the fuel to atomize. If they're blocked then it could be problematic, and cause issues similar to what you're describing. You have to take the jets out of the carbs to clean these holes.

I have a goldwing that sat for years, and when I got the bike fired up it did a similar thing to what you described. It would run on full choke, but die when I gave it gas. I got it to idle off choke eventually, but as soon as I opened the throttle a little it would bog down. When I finally opened the carbs up for cleaning, the idle jets were completely blocked, and the little holes on the main jets were also blocked.

[Tryvelcro]

Did you bench sync them before you put them back on?