I had a similar problem with the carb on my Coupe. It sits for much of the time both in museums and at home. A friend of the group is Bill Silver, he is well versed in Honda bikes and even wrote a couple of books on them. His assistance on this exact problem was invaluable.
It seems the recombined fuels we are burning in our early 70's technology Carb is leaving a gooey mess on the jets. Without pulling the carb completely apart and cleaning everything, you won't get it out. Really, I too had pulled it down to where I thought I would clean everything. But the center jets live in long casting holes that allow this mess to stay there and even with carb-cleaner pushed with compressed air it just doesn't do the job.
So, pull it apart, and just when you think everything is out, look again. Caution, don't remove the throttle assemblies as there are seals there that can be damaged resulting in a vacuum leak.
End result, it acts like a carb again.
Bill
> -----Original Message-----
> From:
> 2cylinderhondas@yahoogroups.com [mailto:2cylinderhondas@yahoogroups.com] > On > Behalf Of > roger white > Sent:
> Tuesday, October 26, 2010 5:29
> PM
> To:
> 2cylinderhondas@yahoogroups.com
> Subject:
> [2cylinderhondas] Where did my idle go?
> Has anyone seen my idle?
> I haven't run my 71' AN600 in a year so I pumped the fuel tank dry > and pulled the bowl on the carb.
> The carb still had some liquid "gas" in it. I sprayed carb cleaner > in bowl and through jets, reassembled and put in a gallon of gas with > stabilizer in the tank. Fired right up but will only run wtih 1/2 to > full choke at fast idle. I let it warm up and it died when I pushed the choke > in. It "sneezed" twice before it died. It was almost like it was > back firing without ignition.
> Does any one have any ideas. I'm thinking the idle circuit in the > carb may have gummed shut.
> How do I check the idle shut off relay?
> Thanks.