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1990 750r fuel flow problem

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  #1  
Old 01-29-2012, 06:10 PM
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Default 1990 750r fuel flow problem

fuel flow from tank to filter ok. Once filter is drained fuel will not flow and bike shuts off. Carbs cleaned twice, tank cleaned and kreemed, all new fuel hoses and fuel petcock rebuilt. Any suggestions?
 
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Old 01-29-2012, 10:01 PM
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Pull the filter for inspection. Is it plugged or clean? I have not replaced my pump yet, start with the filter and as with all fuel pumps of any kind.... do not run them dry.

Note: per pg 15-37 "When fuel level in the float chamber is low, the fuel pump operates to supply fuel into the float chamber. When the fuel reaches a certain level, the fuel pressure rises, and the fuel pump stops."

Section 15-38 electrical section....

bypass the pump for testing using your battery. Pressure of 1.6-2.3 psi reading. If that is good inspect the pump relay.
 
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Old 01-29-2012, 11:28 PM
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Gravity fuel supply...no fuel pump in this model... I think
 
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Old 01-30-2012, 04:32 AM
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Originally Posted by Ripper
Gravity fuel supply...no fuel pump in this model... I think

Dang, forgot that the F models were still available which are vacuum fed. I was going off of my H series checks. I apologize for the confusion.

Check for a pinched or clogged vacuum tap line, air vent plugged, and of course the fuel line or filter screen plugged or the float valve clogged.
 
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Old 02-04-2012, 12:13 AM
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Is the petcock vaccum operated?
 
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Old 02-07-2012, 12:36 AM
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I was thinking "vacuum" related because of how it connects up to the liquid vapor separator and to the canister (Evaporative Emission Control System) with no diaphragm on the fuel tap. .... a bad definition on my part But have you also checked out the separator per your manual?
 
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Old 02-07-2012, 08:38 PM
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vacuum tap line from petcock goes to a BLIND nipple on the carb intake block. Is this correct? Why would a vac line go to a "closed" place?
 
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Old 02-07-2012, 08:39 PM
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it is vacuum operated
 
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Old 02-07-2012, 10:06 PM
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Originally Posted by Ripper
vacuum tap line from petcock goes to a BLIND nipple on the carb intake block. Is this correct? Why would a vac line go to a "closed" place?
Is it connected properly? I agree, why would a vac line go to a closed place, which won't be supplying any vacuum?
 
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Old 02-08-2012, 01:01 AM
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