Topic: 1971 CB500 will not idle. Please help!

[tensi0n]

I have a 1971 CB500 and it will not idle.  The bike will only run when I have the choke on and I crank the throttle halfway+.  I think one of the carbs is not getting the proper amount of gas.  The reason I think is is because after I try to start the bike, there is gas in the carb bowl in only three of the carbs.  The other only had like 2 drops of gas in the bowl.  Could someone please tell me what the problem might be? 

The bike was running just fine about 10 months ago when I got it back from the shop.  It hasn't been run very much until now and I think gasoline has been in the tank since then as well.  Any thoughts?  Thank you.

[bryanj]

Youre goning to have to take the carbs off, strip and clean them

[tensi0n]

aaw man I was afraid of that.  At least I know what I need to do next though.  Thanks for the reply. Was it because the bike was sitting so long?

Also...How do you recommend I clean them?  Can I just take everything apart and use carb cleaner?  Thanks.

[TwoTired]

When gas dried out in the carbs from sitting all tat time, it left sticky varnish residue in your carbs.  The carb that doesn't fill has it's float or float valve stuck.  The very tiny idle jets are now plugged with varnish.  Choke application forces fuel from the much larger main jets when the throttle is opened.
 The float on the dry carb might un-stick by tapping on it.  The slow jets must be removed and cleaned so fuel can pass through them. 
If you have the proper tools and mechanical prowess, this the be done while the carbs are on the bike.  However, if the main emulsion tubes are also varnished up, then the carbs have to be pulled and cleaned.

Cheers,

[Hush]

Heck mate the bike is 37 years old and you want it to idle?you're lucky it goes ha ha.
Seriously I'd say something has gone down the feed line to your 4th carb, you might get away with dropping the bowl only on that one and blowing air with a tube through the tank line.
Also even simpler would be that the float is jamming in the up position thereby stopping fuel filling the bowl.
I'd tinker with it all before stripping the carbs off altogether.
Some fresh gas might help too!

[tensi0n]

Ok I will try the things you guys suggusted.  Thanks for all your help!  It's very much appreciated.   

And I should probably change out that gas too...

[TwoTired]

OK, this sometimes works.

Bike on the center stand.

Disconnect the carb fuel lines.  Remove fuel tank.

Drain all the gas from each carb bowl.  Replace the bowl drain plug.

Pour carb cleaner, or something like Seafoam into the fuel lines till it will take no more.  Let sit overnight.

Put on full choke, leave throttle at idle, ignition off and use the kicker to to turn the crank over 5-20 times.

Drain out the cleaning fluid in the carbs.

Reconnect the tank and fuel lines, turn on gas, and try to start the bike again.  With luck, the cleaner has opened the jets and cleared the float valve.  If not, then systematic disassembly is indicated.

Your call.