Motorcycle Repair: 1982 Honda CB900C, float bowls, fuel starvation

Question
I need help with this bike...it's driving me nuts. I know that there is a charging system, but now it wont start at all. I'm not sure what is wrong now. ive charged the battery after i got home after a ride, now it just wont start, it will turn over just fine and almost start and then stumbles off and dies.  ive checked the petcock, its on, ive checked the in-line filter. i dont know much about bike repair, but i love this bike so i want to get it running. any suggestions or sources for repair manuals would be greatly appreciated. thank you

Answer
Mike,

I guess the first question is "Did you run out of gas?"  Sounds cheeky, but people forget sometimes or think they got gas and/or forgot to switch to reserve position.

http://www.cmsnl.com/honda-cb900c-900-custom-1982-usa_model7250/partslist/F++15....

IF you have rust/corrosion inside the fuel tank, then the petcock passages could be getting clogged, especially of the filter is plugged up/damaged. Make sure your fuel supply is clean and free flowing.

Next, check to see if your carbs have fuel, by opening the drain screws at the bottom of the carburetor float bowls. If little gas runs out then the automatic fuel control may be having issues with a failed diaphragm.

http://www.cmsnl.com/honda-cb900c-900-custom-1982-usa_model7250/partslist/E++21....

If the bike is starting to catch with full choke, then dying, the carbs are not getting fuel.

Next, pull the spark plugs and check for spark by connecting the plugs to the wires and lying the plugs against the cylinder head. DO NOT do this if you have gas fumes/residues present adjacent to the spark source.

If you have spark at all plugs (remember that 1 and 4 are on the same coil and 2 and 3 are on a different coil, then the problem goes back to the fuel starvation.

Make sure that your battery is fully charged and able to pass a load test. These engines are noted for charging system failures. You can find troubleshooting info at www.electrosport.com

Shop manuals can be found on Ebay or at the source: www.helminc.com

Bill Silver