Guest peimei Posted July 23, 2011 Share Posted July 23, 2011 what exactly tells the pump to stop pumping? i put a brand new pump on my bike and it thumps and doesn't feel like it every stops. first gas was blowing out of my float bowl gaskets, put new ones on, now its blowing out of the T joints in between the carbs. thx Link to comment Share on other sites More sharing options...
V4 Rosso Posted July 23, 2011 Share Posted July 23, 2011 Fuel line pressure. When the floats close the fuel line, pressure rises in the fuel line and the pump stops working until pressure drops again (floats open). Link to comment Share on other sites More sharing options...
timmythecop Posted July 23, 2011 Share Posted July 23, 2011 Fuel line pressure. When the floats close the fuel line, pressure rises in the fuel line and the pump stops working until pressure drops again (floats open). this will prolly do in a pinch, but i was going to say "The Force" Link to comment Share on other sites More sharing options...
Member Contributer YoshiHNS Posted July 23, 2011 Member Contributer Share Posted July 23, 2011 Yes. The pump is controlled by pressure. Sounds like you might have a stuck float or something not set up quite right. Link to comment Share on other sites More sharing options...
Guest Posted July 23, 2011 Share Posted July 23, 2011 thanks for the info, i put gobs of new parts on: floats, float valves, bowl gaskets, air filter, fuel pump, fuel pump relay, pulse generator, dynojet kit, micron slip on, VFRness, electrosport R/R, valve check, and 3 sets of plugs. about 1 hour till i fire it up after 4 weekends of troubleshooting. im dying to ride Link to comment Share on other sites More sharing options...
Member Contributer kaldek Posted July 23, 2011 Member Contributer Share Posted July 23, 2011 Fuel line pressure. When the floats close the fuel line, pressure rises in the fuel line and the pump stops working until pressure drops again (floats open). Is it a clicker pump like the old '83 models or just a low pressure roller-vane that has a pressure induced switch inside it? The older models were a pain in the arse - when those old pumps failed they were a nightmare to fix. Link to comment Share on other sites More sharing options...
Member Contributer Jakobi Posted July 23, 2011 Member Contributer Share Posted July 23, 2011 Is it a clicker pump like the old '83 models or just a low pressure roller-vane that has a pressure induced switch inside it? The older models were a pain in the arse - when those old pumps failed they were a nightmare to fix. When the pumps fail on the older models you get rid of them because they're not needed. Problem solved. OP's problem sounds like a stuck float to me. -Jake Link to comment Share on other sites More sharing options...
Guest Posted July 24, 2011 Share Posted July 24, 2011 still not running, stumbles throughout the low to mid and idles like it has a cam in it. im going to bypass the pump and setup a quick gravity feed on sunday, see if that helps me fix this. thx Link to comment Share on other sites More sharing options...
V4 Rosso Posted July 24, 2011 Share Posted July 24, 2011 Is it a clicker pump like the old '83 models or just a low pressure roller-vane that has a pressure induced switch inside it? The older models were a pain in the arse - when those old pumps failed they were a nightmare to fix. Clicker pump. I think he biggest problem with those is that they stop working due to bunred contact points. still not running, stumbles throughout the low to mid and idles like it has a cam in it. im going to bypass the pump and setup a quick gravity feed on sunday, see if that helps me fix this. Before that I would try to manually (e.g. with a clamp) block the fuel from going from the pump to the carbs and see if the pump stops by itself. If it does, it seems the problem is elsewhere. Link to comment Share on other sites More sharing options...
Member Contributer kaldek Posted July 24, 2011 Member Contributer Share Posted July 24, 2011 When the pumps fail on the older models you get rid of them because they're not needed. Problem solved. LOL, I did that to the '83 VF750F I used to own and it made the last three litres inaccessible; it was a crap idea!! Link to comment Share on other sites More sharing options...
Guest Posted July 24, 2011 Share Posted July 24, 2011 Before that I would try to manually (e.g. with a clamp) block the fuel from going from the pump to the carbs and see if the pump stops by itself. If it does, it seems the problem is elsewhere. i actually tried that with the original pump, will give it a go tonight on the new one. my voltage at the ICM is only 11.45 when the bike is not running. there is a possibility the alternator is bad so the pump doesn't have enough voltage to shut-off the pressure solenoid? thx Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted July 26, 2011 Member Contributer Share Posted July 26, 2011 My voltage at the ICM is only 11.45 when the bike is not running. there is a possibility the alternator is bad so the pump doesn't have enough voltage to shut-off the pressure solenoid? It's a VFR, so there's always the possibility of an electrical problem! What do you mean, "ICM"? 11.45v is generally not good anywhere, at any time, except maybe whilst starting... Perhaps you should check your battery and charging voltage, and go from there? Ciao, Link to comment Share on other sites More sharing options...
Guest Posted July 29, 2011 Share Posted July 29, 2011 It's a VFR, so there's always the possibility of an electrical problem! What do you mean, "ICM"? Ciao, ICM... Ignition control module, that big black box hanging on the tail. I just went ahead and ordered a new Electrosport stator and Trugel battery, they are ready to go in when the new alternator gasket gets here. I got my fingers crossed I bought a 87 yamaha tw200 in case this doesnt work this weekend, lol. Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted July 29, 2011 Member Contributer Share Posted July 29, 2011 It's a VFR, so there's always the possibility of an electrical problem! What do you mean, "ICM"? Ciao, ICM... Ignition control module, that big black box hanging on the tail. I just went ahead and ordered a new Electrosport stator and Trugel battery, they are ready to go in when the new alternator gasket gets here. I got my fingers crossed Ah, okay. That is an unusual place to measure voltage, though. Once you install everything you'll have replaced just about everything apart from the wiring harness--I hope that does it. Ciao, Link to comment Share on other sites More sharing options...
Guest Posted July 30, 2011 Share Posted July 30, 2011 Ah, okay. That is an unusual place to measure voltage, though. Once you install everything you'll have replaced just about everything apart from the wiring harness--I hope that does it. Ciao, nah, its a test in the service manual. new stator is installed and working properly, fuel pump continues to pump to much and flood it at idle Link to comment Share on other sites More sharing options...
Member Contributer gll429 Posted July 30, 2011 Member Contributer Share Posted July 30, 2011 Ah, okay. That is an unusual place to measure voltage, though. Once you install everything you'll have replaced just about everything apart from the wiring harness--I hope that does it. Ciao, nah, its a test in the service manual. new stator is installed and working properly, fuel pump continues to pump to much and flood it at idle did you test the carbs WITH OUT the pump? do they still leak? stuff a funnel in the gas line and fill it up. as for ditching the pump.. it can be done.. you do however have to punch a hole in the reserve tube INSIDE the tank.. try testing your carbs 1st.... Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted July 30, 2011 Member Contributer Share Posted July 30, 2011 Ah, okay. That is an unusual place to measure voltage, though. Once you install everything you'll have replaced just about everything apart from the wiring harness--I hope that does it. Ciao, nah, its a test in the service manual. new stator is installed and working properly, fuel pump continues to pump to much and flood it at idle Having a non-running bike myself, I can understand your frustration... You can run a VFR750F w/o the fuel pump, just by re-routing the hoses. I did this on the side of the Autobahn once, and ran the bike that way for months. You may have to do something to be able to use the entire tank--I didn't let it get less than 1/3 full. Are you sure you have not inadvertently fitted a high-pressure fuel pump? The OEM pump does not generate enough pressure to blow fuel out of the carbs under normal circumstances. As for the voltage, I'm still a bit puzzled as to why you are concerned about it, and as I said before, 11.anything volts is too low. I also could not find any tests in the Honda or Haynes manuals that called for testing the ICU voltage (except when you're testing the ICU itself). However, for reference purposes, I tested my '93 and got 12.62v at the ICU connector, with the ignition switched "on" and the kill switch in the "run" position. This was approximately 0.2v lower than the voltage at the battery (with ignition "off", but battery connected). I'm still not sure why you've replaced all of the charging system components, but I suppose it can't hurt. Ciao, Link to comment Share on other sites More sharing options...
Guest Posted July 30, 2011 Share Posted July 30, 2011 Ah, okay. That is an unusual place to measure voltage, though. Once you install everything you'll have replaced just about everything apart from the wiring harness--I hope that does it. Ciao, nah, its a test in the service manual. new stator is installed and working properly, fuel pump continues to pump to much and flood it at idle did you test the carbs WITH OUT the pump? do they still leak? stuff a funnel in the gas line and fill it up. as for ditching the pump.. it can be done.. you do however have to punch a hole in the reserve tube INSIDE the tank.. try testing your carbs 1st.... i unplugged the fuel pump while the bike was running and the bike starts to slowly run better without the pump. no leaks anywhere with the carbs. might try the gravity feed tonight so i can at least take it for a cruise around town. peimei Link to comment Share on other sites More sharing options...
Guest Posted July 30, 2011 Share Posted July 30, 2011 Ah, okay. That is an unusual place to measure voltage, though. Once you install everything you'll have replaced just about everything apart from the wiring harness--I hope that does it. Ciao, nah, its a test in the service manual. new stator is installed and working properly, fuel pump continues to pump to much and flood it at idle Having a non-running bike myself, I can understand your frustration... You can run a VFR750F w/o the fuel pump, just by re-routing the hoses. I did this on the side of the Autobahn once, and ran the bike that way for months. You may have to do something to be able to use the entire tank--I didn't let it get less than 1/3 full. Are you sure you have not inadvertently fitted a high-pressure fuel pump? The OEM pump does not generate enough pressure to blow fuel out of the carbs under normal circumstances. As for the voltage, I'm still a bit puzzled as to why you are concerned about it, and as I said before, 11.anything volts is too low. I also could not find any tests in the Honda or Haynes manuals that called for testing the ICU voltage (except when you're testing the ICU itself). However, for reference purposes, I tested my '93 and got 12.62v at the ICU connector, with the ignition switched "on" and the kill switch in the "run" position. This was approximately 0.2v lower than the voltage at the battery (with ignition "off", but battery connected). I'm still not sure why you've replaced all of the charging system components, but I suppose it can't hurt. Ciao, new fuel pump is the genuine honda part number. the ICM test was in the 90-96 honda service manual page 16-6. i was using it before my 97 manual arrived, ive tested everything on the bike so might as well do all the tests on the ignition system also, in case my spark is weak in the lower RPM, causing it flood. voltage might be concern, another VFR750 owner experienced the same issue of the pump not stopping, his ended up being the stator. if you open the black end cap (like i did with my old pump) you can see the way the pump shuts itself off. so low voltage might not let the switch turn off. your voltage is alot higher than mine, i did the current leakage test (97 honda manual page 16-8). to help check for shorts with a multimeter in between the battery ground cable and the battery and its within spec. .58 ma Link to comment Share on other sites More sharing options...
Guest Posted August 2, 2011 Share Posted August 2, 2011 JZH.........I just ordered a Facet pump 2 days ago, then a few minutes ago came across a pic you posted that has one, lol Which model did you end up using? I bought both a 40171 (3-4 psi) and 40177 (1-2 psi) for testing. Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted August 2, 2011 Member Contributer Share Posted August 2, 2011 JZH.........I just ordered a Facet pump 2 days ago, then a few minutes ago came across a pic you posted that has one, lol Which model did you end up using? I bought both a 40171 (3-4 psi) and 40177 (1-2 psi) for testing. 40105. Your 40171 is probably better suited to this application, but I don't think they made that one when I bought mine. I thought I had an install thread on here about it, but I cannot find it now. Basically, I just bought the pump that the Africa Twin guys were using to replace their similar, failing OEM Mitsubishi pumps. Ciao, Link to comment Share on other sites More sharing options...
Guest Posted August 3, 2011 Share Posted August 3, 2011 JZH.........I just ordered a Facet pump 2 days ago, then a few minutes ago came across a pic you posted that has one, lol Which model did you end up using? I bought both a 40171 (3-4 psi) and 40177 (1-2 psi) for testing. 40105. Your 40171 is probably better suited to this application, but I don't think they made that one when I bought mine. I thought I had an install thread on here about it, but I cannot find it now. Basically, I just bought the pump that the Africa Twin guys were using to replace their similar, failing OEM Mitsubishi pumps. Ciao, i found my model number from the KTM 950 owners having troubles with there mitsubishi pumps. you may consider upgrading someday, both my models have check valves in case something goes wrong http://www.facet-purolator.com/index.php?option=com_content&task=category§ionid=7&id=16&Itemid=31 pumps should be here tomorrow, im guessing the 3-4 psi will be the better one the Facet tech said these pumps lose 1 psi every 12 inches of hose it has to travel. Link to comment Share on other sites More sharing options...
Guest Posted August 6, 2011 Share Posted August 6, 2011 new pump,,,,, still doesnt run. floats are fine also, i can blow threw the fuel inlet and then turn the carb assemblies upside down and they seal up good. im out of ideas kill this thread Link to comment Share on other sites More sharing options...
V4 Rosso Posted August 6, 2011 Share Posted August 6, 2011 floats are fine also, i can blow threw the fuel inlet and then turn the carb assemblies upside down and they seal up good. Have you inspected the float bowls as this indicates the float bowls are leaking and filling up with petrol. Link to comment Share on other sites More sharing options...
Guest Posted August 6, 2011 Share Posted August 6, 2011 floats are fine also, i can blow threw the fuel inlet and then turn the carb assemblies upside down and they seal up good. Have you inspected the float bowls as this indicates the float bowls are leaking and filling up with petrol. brand new floats and float valves. im looking for a used Ignition control module now, most everything else is new. Link to comment Share on other sites More sharing options...
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