bike won't run

[Ry_Guy]

The situation:
- 96 gs, won't run. When it did, it would die if I didn't keep feeding it gas.

What I did:
- float height check (passed)
- spark plug check (passed)
- vacuum check; sprayed wd40 around intake boots (passed)
- adjusted the fuel/air mixture idle screw
- replaced the fuel valve (it was indeed broken)
- carbs and tank were cleaned five thousand miles ago
- had the choke cable and air filter replaced five thousand miles ago
- cleaned the tank out and inspected for signs of rust

The symptoms:
- by inspection of the fuel filter, I see that fuel won't go into the carbs now even with the switch on PRI.
I'm pretty sure the hoses are routed correctly- I followed the fuel hose routing diagram http://www.bbburma.net/FuelHoseRouting.htm after reinstalling the fuel valve.
- by inspection of the spark plugs, they look like they're supposed to.

Could it still be a vacuum related prob?  :dunno:  

Thanks for listening  

[John Bates]

Have you checked the gas cap vent. If it's plugged it will stop the flow of fuel.  

Search for "gas cap", check the "search for all terms" box.  The fifth topic may be helpful.

[werase643]

open the tank....fuel flowing on pri?
if no...floats sound like they are stuck shut
try draining the float bowls..... and see if more fuel flows in...

[Kerry]

- by inspection of the fuel filter, I see that fuel won't go into the carbs now even with the switch on PRI.

Hmmm ... fuel filter, eh?  Is there any chance that the filter itself is clogged?  Here are some things to try.  I'm assuming that the fuel filter is in between the ON/RES/PRI fuel selector and the lower T-connector on the carbs:

1) Make sure you have plenty of fuel in the tank.  If you can see the "hump" in the forward part of the tank, add some more.

2) Make sure the petcock under the fuel tank is in the ON (vertical) position:

3) Try werase643's suggestion.  With the fuel selector set to PRIme and a catch can ready, loosen one of the carb drain screws.

Does the carb drain?  If not, check the vent hose that attaches to the upper T-connector on the carbs and drapes over the airbox.  Is the free end of that hose open to the air?  It should NOT be plugged.  If the vent hose looks OK then the problem is probably inside the carb.

If the carb DOES drain, does fuel flow through the fuel filter at the same time?  If so, then everything upstream is OK (on the PRI setting anyway) and you may have a vacuum problem between the carb and the fuel selector when using the ON or RES positions.

4) If fuel does NOT flow through the filter, then pull the hose from the carb end of the fuel filter and see if fuel flows directly through the filter.  If it does NOT, then the filter itself may be the problem.  To find out, pull the fuel filter from the "upstream" hose and see if fuel will flow.

5) If fuel doesn't even flow from the hose between the fuel selector and the fuel filter, then the fuel selector may be the problem.  Find out by pulling the RES hose from its inlet at the fuel selector.

6) If fuel STILL doesn't flow, then the problem is either in the RES hose itelf or the in-tank petcock or filter screen.[/list:u]