Carb help needed

[Pop]

87 VR. Been in storage for 10 years after problems with carbs. Tank was full of rust so I pulled it and re coated it inside. I then pulled the carb bank, cleaned it, and reinstalled. Could not make it idle then so gave up on it and stored it. Bought a goldwing and a KLR 650 which I have been riding. Decided it was time to try again on the VR.

 Pulled the carbs and cleaned them again, no help. Then I bought the Harbor Freight ultrasonic cleaner and cleaned each carb completely disassembled and blew compressed air through every port. Attached the air cleaner box and used a funnel with tubing connected to the carb bank fuel input port so it is clean gas going in.

All that only made worse. It will idle for short runs so it has spark. Will start with choke but won't keep running. Opening throttle kills it. Classic pilot jet clog but I don't know how to get the carbs any cleaner. With air cleaner off I can feel strong vacuum on the carb air cleaner ports. Even tried starter fluid. Pilot screws were at 2 1/2 out. Tried 4 out. Plugs are carbon covered but dry. Can't sync since it won't idle but all closed and looked even when bench syncd. Anything else I should try? Any ideas? Thanks! 

 

 

[Pasta Burner]

Fuel pump?  I’m a carb newbie but is the gravity feed enough pressure?

[cowpuc]

I 100% agree with Pasta,, I have a gut feeling that there is no way gravity feed trying to fill 4 carbs is gonna be able to keep up by using a funnel. If you had the weight of a few gallons of gas pushing the fuel in then yeah,, that should fly but not with a funnel. Maybe hook it back up to the funnel,  start it and let it idle till it quits as you say and then unhook the funnel when it dies and open the carb drains and see how much fuel you get out of them, you might be surprise to find the bowls are almost empty. I would test the fuel pump and get the system back to working or at least hook the pump up to the funnel at its input and output the pump to the carbs @Pop.  After you try that and if it still wont go start answering a few of these questions please.. Did you run a sizing wire thru the jets, both mains and low speed or replace them all? Did you shoot carb cleaner thru the low speed circuitry and physically see carb cleaner come out of the tiny holes in the throats of the carbs? Did you check float height levels on each carb? Are you sure you have the firing order correct on the plugs? Blackened plugs? I have found that these "D" plugs really dont take to kindly to blackening. Plugs are cheap, grab a new set and start fresh, gap em at .030. Check the caps for carbon tracking and wires for corrosion where the caps screw onto them. While you got the plugs out drop a compression tester on her and see what you get.. 

Edited July 9, 2022 by cowpuc

[Marcarl]

10 hours ago, cowpuc said:

I 100% agree with Pasta,, I have a gut feeling that there is no way gravity feed trying to fill 4 carbs is gonna be able to keep up by using a funnel. If you had the weight of a few gallons of gas pushing the fuel in then yeah,, that should fly but not with a funnel. Maybe hook it back up to the funnel,  start it and let it idle till it quits as you say and then unhook the funnel when it dies and open the carb drains and see how much fuel you get out of them, you might be surprise to find the bowls are almost empty. I would test the fuel pump and get the system back to working or at least hook the pump up to the funnel at its input and output the pump to the carbs @Pop.  After you try that and if it still wont go start answering a few of these questions please.. Did you run a sizing wire thru the jets, both mains and low speed or replace them all? Did you shoot carb cleaner thru the low speed circuitry and physically see carb cleaner come out of the tiny holes in the throats of the carbs? Did you check float height levels on each carb? Are you sure you have the firing order correct on the plugs? Blackened plugs? I have found that these "D" plugs really dont take to kindly to blackening. Plugs are cheap, grab a new set and start fresh, gap em at .030. Check the caps for carbon tracking and wires for corrosion where the caps screw onto them. While you got the plugs out drop a compression tester on her and see what you get.. 

And make sure you have the air filter in place with the lid on.

[Pop]

Thanks for the replies. My fuel pump is not working as stated in a previous post. I will try again Monday to find a replacement that will work. I did not realize the float bowls needed pressure. I thought vacuum drew the fuel mixture in. 

I just drained front left and right rear carbs {the ones I could get tubing on} and sure enough they were almost completely empty. I tried pouring more gas into the funnel and front left and right rear are now puking gas out the top. They were not doing this before. So I need to pull the carbs again to look at the float needles. Maybe you could advise me on how to check the float adjustment. The fuel pump will be the next thing I try for sure.

I did not run wires through jets, I saw light through them and used air pressure to blow through every port. Which ports are the low speed circuitry to blow carb cleaner through? Where do you put the carb cleaner straw. I have not been able to find a procedure to check float height and I don't have the tool the service manual calls for. When the carbs were apart I did check that they cut off fuel flow. I tried with the air cleaner box on and tight. All I'm trying to do now is make it idle. Do you need the air box on for that? I had found a fuel pump for a Royal Star. Could I use that with my original bracket? Or maybe a Vmax pump? Or the Orielleys pump? Even the used pump. I would like to replace all the carb parts but prices are insane! The jet block gaskets were something like $20 or so, would be around $80 and shipping was also around $20! Four small pieces of cardboard or whatever for $116 shipped? They could put them in a letter envelope and slap a postage stamp on it for a bit less than $20! I will get new plugs and check the compression. Thanks for all the replies. I now have things to try I did not think of.

 

 

[Pop]

After thinking about it I decided not to pull the carbs for the float valve leak. With pressure on the fuel in the bowls it would help force the float to seal, right? What if after filling the bowls from the funnel I put some pressure on the funnel tubing about 5 psi to see if that would do what a fuel pump would? I think I'll try that.

[Pop]

That didn't work. Will wait till I get a fuel pump to try anything else.

[cowpuc]

2 hours ago, Pop said:

Thanks for the replies. My fuel pump is not working as stated in a previous post. I will try again Monday to find a replacement that will work. I did not realize the float bowls needed pressure. I thought vacuum drew the fuel mixture in. 

Many years ago, right after purchasing my 1st MK1 in 1987 and just before heading cross country on it with one of my kids in tow I went over the bike looking for potential on road issues and noticed it was fueled via electric pump. Knowing the potential for failure (nice thing about gravity is you can always count on gravity being there) I started carrying a length of fuel line to attach to the tank vent line so I could pressurize the tank and get out of the back country of the Utah mountains when Murphy ruined my fuel pump out there. It worked!! Knowing that, what I would do before buying a new pump Pop and just to make sure the bike was worth investing into is pull the pump and splice the inlet/output lines on the pump together with a small piece of tubing. Then disconnect the tank vent line above the restrictor found under the right side plastic cover. The vent line follows the frame downwardly toward the rear brake peddle, the restrictor/back flow preventer/check valve is a small black/white device spliced into the vent line. Pull the line from the restrictor on the tank side of the restrictor and splice a nice  long section of fuel line onto it. Now with the tank cap on you will be able to pressurize your fuel tank with 3 pounds of pressure real easy with your mouth and be able to feel the carbs floats opening and closing with your tongue holding pressure on the tank as you work on the carbs. Believe me it works and this little trick works AMAZING for getting out of bad situations if you ever loose a fuel pump out in the desert. No, vacuum does not draw the fuel in, it is pumped in under 3 psi of pressure. 

I just drained front left and right rear carbs {the ones I could get tubing on} and sure enough they were almost completely empty. The drain lines for each carb should extend from a little plate just below the carb slide covers, if they dont replace them and slip them thru those holes so the drain lines are easy to aquire and work with. I tried pouring more gas into the funnel and front left and right rear are now puking gas out the top. Stuck floats or non functional float needle and seat valves cause this and this can cause hydrolocking. They were not doing this before. So I need to pull the carbs again to look at the float needles. Maybe you could advise me on how to check the float adjustment. It is common practice in bike shops and small engine shops to attach a clear fuel line to the drain hose on carbs and then fill the bowl, open the drain while holding the clear line exterior of the carb to see where the fuel level is at in the bowl. Many years ago, before lazer levels, us guys in the building trades used this same "clear line filled with water" idea to set steel on contruction sites. its very effective. The fuel pump will be the next thing I try for sure.

I did not run wires through jets, I saw light through them and used air pressure to blow through every port.  There is no way of being sure the jets are clean and debris is not altering the jet size without running sizing wire thru them unless you are using new jets. Are you familar with Oxy/Act torch tip cleaners? Carb jet sizing wires look identical. You cant use torch tip cleaners though unless you are VERY careful not to over size the jets, especially the teeny low speed jets. Which ports are the low speed circuitry to blow carb cleaner through? If you pull the bowl covers note the jet where the needle hanging from the bottom of carb slide slips into. Its the bigger of the two jets. That is the high speed jet. The smaller, removeable jet is the low speed jet. Remove the low speed jet so you can clean it with a sizing wire. While its out, stick the straw of the carb cleaner can you are working from snuggly in the hole that the jet came from and hold in snuggly in place against the hole internally of the jet pocket. WEARING GLASSES, hit the spray and look down the throat of the carb with the throttle plate held open. You should see spray coming from the holes before/after the spot in the carb throat where the throttle plate sits when its relaxed in a closed position. these holes are tiny and not uncommon to be dirt filled.  Where do you put the carb cleaner straw. I have not been able to find a procedure to check float height and I don't have the tool the service manual calls for. A $10 set of Harbor Frieght digital calipers should be in every tool box. When the carbs were apart I did check that they cut off fuel flow. I tried with the air cleaner box on and tight. All I'm trying to do now is make it idle. Do you need the air box on for that? No, at idle with the throttle plates closed you should not need the breather cover on. You should be able to get a fairly good idle so you can watch the carb slides in the carbs move as the bike idles. Be warned though, that cover and air filter must be in place to get a good sync.  I had found a fuel pump for a Royal Star. Could I use that with my original bracket? Or maybe a Vmax pump? My gut tells me either will work fine by made need some altering to fit OEM mount. Or the Orielleys pump? Even the used pump. I would like to replace all the carb parts but prices are insane! The jet block gaskets were something like $20 or so, would be around $80 and shipping was also around $20! Four small pieces of cardboard or whatever for $116 shipped? They could put them in a letter envelope and slap a postage stamp on it for a bit less than $20! AGREED!! Its insane isnt it? Think the Ventures are bad, be very very very thankful you arent dealing with a carbed 1500 Honda wing. When Mom Honda decided to move the carbs up off the heads on the earlier Wings to a location between the frame spars she created a nightmare.. My shop was getting $1000 just to pull carb bank (it was actually a small 2 barrel carb setup, cute but a nightmare to work on) from between the frame spars. It was that bad.  I will get new plugs and check the compression. Thanks for all the replies. You bet, glad to help. I now have things to try I did not think of.

 

 

 

[cowpuc]

3 hours ago, Pop said:

After thinking about it I decided not to pull the carbs for the float valve leak. With pressure on the fuel in the bowls it would help force the float to seal, right? No,, the pressure of the fuel fills the bowls and the float rising is what closes the valve. I think you may be thinking the needle that seats against the seal point is exterior of the float bowl so pressure from the pump is what is closing the valve. It is not. What if after filling the bowls from the funnel I put some pressure on the funnel tubing about 5 psi to see if that would do what a fuel pump would?  That should work fine as long as there is enough fuel in the line between the funnel and the carbs you should be able to disconnect the hose from the funnel and finish filling the bowls just but putting pressure on the line with your mouth. I think I'll try that.

 

[Pop]

Thanks cowpuc, I'll let you know what I find when I try all that you suggested. May be a few days til I get it done.

[cowpuc]

2 hours ago, Pop said:

Thanks cowpuc, I'll let you know what I find when I try all that you suggested. May be a few days til I get it done.

You bet Pop, anytime. All the best in getting her up and running my friend. Puc

[Pop]

So I decided to open the fuel pump up and test it some more. I re seated the contacts and spring and shaft and put it all back together. I hooked it up to gas tank and connected the cable. I turned the ignition to on and heard one slight thump from the fuel pump. I had the output connect to an empty pail. No output and the pump was not cycling. So I pulled it off and bench tested it with a 12v battery and it will make a thump sound which is the shaft moving. I then hooked the fuel input with tubing to a cup of water and the output to an empty cup. When I apply voltage to the connector the water draws to the pump then slowly drains back. But if I quickly apply and disconnect like it is supposed to it works great and fills the empty cup nicely. Looking at the wiring diagram there is a fuel pump control relay. Any idea where it is and how to test it and heaven forbid a place to find a replacement? Thanks!

[Pop]

Been round and round with this thing. Just gonna go ahead and order a new pump like I was going to do in the first place.

[Pop]

Cowpuc, I would like to go ahead and buy your used fuel pump. Please reply back or message me. Thanks!

[cowpuc]

3 hours ago, Pop said:

Cowpuc, I would like to go ahead and buy your used fuel pump. Please reply back or message me. Thanks!

Sounds good @Pop.. I just got on here and found this.. Probably the quickest/easy way to proceed is with Paypal if you have such? I will drop it in a USPS Flat Rate box as that seems to be the best way to get it to you quickest at a reasonable rate if thats OK? I also have a brand new aftermarket one for a Gen 2 that you could also have for the same $$,, $35 shipped.. Just let me know here.. Puc

[Pop]

Just the old style one Cowpuc.

[cowpuc]

1 hour ago, Pop said:

Just the old style one Cowpuc.

Roger that @Pop,, lets complete it in the P.M.'s. I will send you my email/Paypal info there and get the pump right out to you tomorrow. 

[Pop]

Ok. Thanks

[cowpuc]

and your fuel pump is on its way Pop. It should be in your hands by Saturday. You should be riding by Saturday evening brother as it checked out fine here. All the pertinent info, including tracking number are in your P.M.'s @Pop. All the best my friend! Puc

[Pop]

Got the fuel pump on and it works great! Got an overflow on one carb. Have pulled carbs and adjusted float levels. Will put them back in and go from there tomorrow.

[cowpuc]

13 hours ago, Pop said:

Got the fuel pump on and it works great! Got an overflow on one carb. Have pulled carbs and adjusted float levels. Will put them back in and go from there tomorrow.

OUTSTANDING!! Thanks for the update @Pop! MANY MANY MANY fantastic miles to you and your scoot!

[Pasta Burner]

16 hours ago, Pop said:

Got the fuel pump on and it works great! Got an overflow on one carb. Have pulled carbs and adjusted float levels. Will put them back in and go from there tomorrow.

Glad it’s working for you!  I was a bit worried suggesting something that might not be it.

[Pop]

I've got it idling fairly well after putting the airbox back on and doing a sync. Having trouble setting the idle to 1000 as the rpm's will occasionally surge faster. I can adjust the idle down then it will be too low. I adjust it up and after a bit the rpms will zoom to 2 or 3k. I was getting a lot of smoke off the hot engine from dirt and oil buildup from past overflows. I wanted to move it out from the garage to the driveway to wash it off. Found out the brake front master cylinder was empty and rear was not working either. Need the front brake since my driveway is slanted toward the street. I came in to research this brake operation. I want to pull the front master cyl off and look at the piston in it. How does the brake light switch come off. Are there any other resources I can look at on this?

[Pasta Burner]

Hey @Pop the brakes are linked meaning if nobody has modified it already the lever activates the front right caliper and the pedal activates the front left and rear.  The switch I’m not sure off hand.

[Pop]

Thanks for the reply. I think I will start a new thread on brakes.