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Discussion Starter · #1 ·
Checked fuel pump , replaced fuel lines , Starts when gas is poured into carbs but only till gas is burned out . No fuel getting to carbs ? What do I need to do next . Can't afford to take it in . I have the carbs off and on them bench .
 

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What bike is this? I would check the tank filter/vacuum. If its a vacuum operated fuel valve there should be a vacuum line from a nipple somewhere on the head/barrel/one of the carbs/fuel rail to provide vacuum. To check simply pull off the fuel line and get the motor running with a squirt of fuel. Fuel must flow if not then there is no vacuum or the diaphrqgm inside is toast. Does the pump prime and does it flow fuel....again fuel line off and a ignition on. If the pump filters are clogged then a revers flush may work....even just to the extent of identifying the fault.

Good luck
 

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Discussion Starter · #3 ·
What bike is this? I would check the tank filter/vacuum. If its a vacuum operated fuel valve there should be a vacuum line from a nipple somewhere on the head/barrel/one of the carbs/fuel rail to provide vacuum. To check simply pull off the fuel line and get the motor running with a squirt of fuel. Fuel must flow if not then there is no vacuum or the diaphragm inside is toast. Does the pump prime and does it flow fuel....again fuel line off and a ignition on. If the pump filters are clogged then a revers flush may work....even just to the extent of identifying the fault.

Good luck
I'm not finding any such vacuum line all 4 carbs have diaphragms. I'm not a mechanic so things need to be very simple I'm also an old fart and just trying to get this thing ready to sell . It was running great prior to our summer heat 110 degrees in the shade . put it up with some fuel additive to keep gas from turning to glue . Fuel pump works when running but no throttle to keep it running after gas burns off , No squirt of fuel from carbs .
This is the best I can describe my problem .
 

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Fuel pump works when running but no throttle to keep it running after gas burns off , No squirt of fuel from carbs .
This is the best I can describe my problem .
What exactly are you doing to "test" the fuel pump ?

It sounds a LOT like a clogged fuel filter or that you are getting no power to the pump or the pump has ZERO output even though it is "running".
 

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Discussion Starter · #5 ·
What exactly are you doing to "test" the fuel pump ?

It sounds a LOT like a clogged fuel filter or that you are getting no power to the pump or the pump has ZERO output even though it is "running".
Pump runs and when taken off the input to carbs it shoots gas out . Filter seems OK as the gas does get thru it . Right ?
This thing run good just before I shut it down for summer . I do not ride after it hits 100 degrees . I am currently cleaning carbs ( off the bike ) Pulled jets etc. and sprayed carb cleaner thru all the insides . Just on 2nd carb now .
 

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Discussion Starter · #6 ·
I'm not finding any such vacuum line all 4 carbs have diaphragms. I'm not a mechanic so things need to be very simple I'm also an old fart and just trying to get this thing ready to sell . It was running great prior to our summer heat 110 degrees in the shade . put it up with some fuel additive to keep gas from turning to glue . Fuel pump works when running but no throttle to keep it running after gas burns off , No squirt of fuel from carbs .
This is the best I can describe my problem .
Found vacuum stuff ,
 

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Discussion Starter · #8 ·
If......there is a fuel pump, there probably is NOT a vacuum operated petcock too; no need for both.

So, hopefully when you get the carbs all back together it will work better.
Might need to run some cleaner through with fresh gas to finish the job though.
Thanks . Throttle cables driving me crazy today . I had to stop before it accidently caught on fire just as I pushed it out of the garage :mad:
 

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Checked fuel pump , replaced fuel lines , Starts when gas is poured into carbs but only till gas is burned out . No fuel getting to carbs ? What do I need to do next . Can't afford to take it in . I have the carbs off and on them bench .
The only suggestion I have on that is try to remove the cap on your gas tank. Sometimes the seal can be too tight and stop the air flow, and the fuel flow.
 

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Discussion Starter · #11 ·
Still will not run . I am out of ideas, plus springs keep falling out , so back off and try to find solution to these issues .
Well back on everything hooked up ok . Runs for 20 seconds and runs out of gas . Twist the throttle a few times it runs but if I hit the throtal it stalls out and dies again . WTH . .I do not know what to do . Got carbs off again What should I do nxt ????
 

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Ok time to step back and consider what is happening. From your posts it seems the fuel is getting to the carbs. From there to the engine is either through the idle circuits or the main jet. The main jet is worked by one of two systems. Yours are vacuum operated which means a diaphragm in each carb causes a vacuum to lift the slide and needle clear of the main jet with the needle metering the fuel as it rises.

The idle circuit works at about full closed throttle to 1 1/8 open throttle when the needle and main jet take over. It would seem this is the point where your engine falters and stalls. It follows then, that the idle circuits are not working properly or one or more diaphragms are not raising the slides/needles.

My suggestions are 1: Run some good quality carb cleaner throught and leave overnight or longer if possible....do this with them on the bike so vacuum can pull the cleaner all the way through the tiny idle circuits.

2: Remove the carb caps one at a time and check the following. The diaphragms have no pin holes in them....check against a strong light.

All 'O' rings are fitted...most CV carbs have a tiny 'O' ring in the top that allows the idle circuit to draw extar air.

Float needle tips are in good condition with no ring around the tips.

Float heights are all set correctly.

The return springs are not cocked over or otherwise tangled. The latter is easier to set up by having the cap off and slowly lowering it and the spring into position while holding the slid in the up position with your finger. This allows the spring to correctly locate on the slide top and the cap recessed lip. The air filter will need to be off to do this.

If non of the above helps then post and we'll try to help again.

One final thing to check is a possible air leak at either end of the carb boot/s. Overtightening of the clamps can cause the boot/s to bulge letting in air. Also any pin holes or cracking can do the same.

Good luck
 

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Discussion Starter · #13 ·
Ok time to step back and consider what is happening. From your posts it seems the fuel is getting to the carbs. From there to the engine is either through the idle circuits or the main jet. The main jet is worked by one of two systems. Yours are vacuum operated which means a diaphragm in each carb causes a vacuum to lift the slide and needle clear of the main jet with the needle metering the fuel as it rises.

The idle circuit works at about full closed throttle to 1 1/8 open throttle when the needle and main jet take over. It would seem this is the point where your engine falters and stalls. It follows then, that the idle circuits are not working properly or one or more diaphragms are not raising the slides/needles.

My suggestions are 1: Run some good quality carb cleaner throught and leave overnight or longer if possible....do this with them on the bike so vacuum can pull the cleaner all the way through the tiny idle circuits.

2: Remove the carb caps one at a time and check the following. The diaphragms have no pin holes in them....check against a strong light.

All 'O' rings are fitted...most CV carbs have a tiny 'O' ring in the top that allows the idle circuit to draw extar air.

Float needle tips are in good condition with no ring around the tips.

Float heights are all set correctly.

The return springs are not cocked over or otherwise tangled. The latter is easier to set up by having the cap off and slowly lowering it and the spring into position while holding the slid in the up position with your finger. This allows the spring to correctly locate on the slide top and the cap recessed lip. The air filter will need to be off to do this.

If non of the above helps then post and we'll try to help again.

One final thing to check is a possible air leak at either end of the carb boot/s. Overtightening of the clamps can cause the boot/s to bulge letting in air. Also any pin holes or cracking can do the same.

Good luck
Thanks and I'll see if I can do this . Some I understand some not so much . I did notice that thhe slides were very sticky when pushed up by hand . Not sure what caused that however . This seems to be over my head right now but I will try .The boots are new from the last issues I had . .
Thanks
 

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Discussion Starter · #14 ·
Thanks and I'll see if I can do this . Some I understand some not so much . I did notice that thhe slides were very sticky when pushed up by hand . Not sure what caused that however . This seems to be over my head right now but I will try .The boots are new from the last issues I had . .
Thanks
Checked all the diaphragmes , no holes . One was very dirty with some kind of sticky stuff on it . Went thru the carbs again ( cleaned ) Fuel pump shoots gas 1/2 out of the garage so I thinks its good . Hooked up everything and tried to start . NO GO refused to fire up .Cranked it till the battery went dead Nothing . Waiting for battery to charge now . WTH is up with this thing ??? Don't know what to do any more ,
 

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Don't know what to do any more ,
Sorry to say but......not everybody can do everything.
If you are not a trained mechanic, you shouldn't necessarily expect to be able to fix all problems with all vehicles.


Sounds like you need some on site help, or a shop visit.
Sometimes the tiny jet passages in a carb get SO tightly plugged that a new carb is necessary.
 

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Discussion Starter · #16 ·
Sorry to say but......not everybody can do everything.
If you are not a trained mechanic, you shouldn't necessarily expect to be able to fix all problems with all vehicles.


Sounds like you need some on site help, or a shop visit.
Sometimes the tiny jet passages in a carb get SO tightly plugged that a new carb is necessary.
Thanks . You'r right . I just wanted to get it to sell . My back issues will not allow me to ride anymore . So I guess I could try to get rid of it some way , not running . It ran so good at first , very fast little bike .
 

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Final thing I would suggest is pull the plugs to check if they are wet....if not then its from carbs to engine, which is already suspected.....you may find it is only one or more that are dry and this will indicate which if any carbs are having issues.

Good luck
 

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Discussion Starter · #18 ·
Final thing I would suggest is pull the plugs to check if they are wet....if not then its from carbs to engine, which is already suspected.....you may find it is only one or more that are dry and this will indicate which if any carbs are having issues.

Good luck
Well pulled the plugs . 2 rear wcere wett , 2 fdry . I have not checked the diaphrams out to see if there is a twist in any of them . Later today I'll do that . So what's next IYHO . I'm afraid to even try to start it now ( better not to know ) ;0)
Any other opinions are welcome . I think .
Arley
 

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Discussion Starter · #19 ·
Well pulled the plugs . 2 rear wcere wett , 2 fdry . I have not checked the diaphrams out to see if there is a twist in any of them . Later today I'll do that . So what's next IYHO . I'm afraid to even try to start it now ( better not to know ) ;0)
Any other opinions are welcome . I think .
Arley
Well pulled the plugs . 2 rear wcere wett , 2 fdry . I have not checked the diaphrams out to see if there is a twist in any of them . Later today I'll do that . So what's next IYHO . I'm afraid to even try to start it now ( better not to know ) ;0)
Any other opinions are welcome . I think .
Arley
Well here's the new finding right front carb no gas in the bowl as evedenced by loosening bowl screw . No gas . All others have gas in them . ??What to do now ?
 

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On multi cylinder bikes just one carb not working can prevent the engine running properly...I know from experience.

So the offending carb needs to be investigated. The float needle may be sticking/need replacing....any evidence of a ring around the tip indicates it needs replacing. The common fuel rail may be blocked. pretty much thats about it....there are only a couple of things that would prevent a carb bowl filling I cant think of any more than mentioned.

Good luck
 
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