Motorcycle Repair: throttle issues, 1981 honda cx500, vacuum petcock

Question
1981 honda cx500 trike. sitting for 2 years, starts fine, idles between 1500-2000, but as soon as I throttle, it bogs down and it stalls, I've let the trike idle for an hour, yet it won't idle above 2k rpm, it will momentarily, then it bogs down, I let go of the throttle, then it idles normally. Could it be a problem with the choke valves?

Answer
Richard...  You might have any of the following issues....

-Carburetor main jets plugged up ... likely when a bike has been sitting with old fuel in the system.

-Ignition failure in one side... due to bad spark plug, spark plug cap, coil or pulse coil...

http://www.elsham.pwp.blueyonder.co.uk/cx500/stator/

-Vacuum petcock diaphragm failure causing an air leak and lack of fuel delivery.

If it starts fine and idles okay, then the problem is probably fuel, but check that link above for a good ignition system evaluation.

Look at illustrations at sites like www.bikebandit.com for parts in question.

Bill Silver