fuel problems
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fuel problems
Hello, I have a 73 Ironhead with a keihin carb I cant get any fuel into it.
I set the float at 14mm and changed the petcock to a 90 deg barb and still nothing. the fuel inlet is pointing downward and wondering if it should be faceing up or if the way the fuel line is run if that would make a difference. any help would be great thanks.
I set the float at 14mm and changed the petcock to a 90 deg barb and still nothing. the fuel inlet is pointing downward and wondering if it should be faceing up or if the way the fuel line is run if that would make a difference. any help would be great thanks.
The stock carb for 1973 is a Bendix. Tell us more about the Keihin. Is it a CV or a butterfly carb? Some Keihins [1976 - 1978] have two float adjustments, a high and a low, to be set. Later ones need a 16 to 17 mm level set.
You should examine the in-tank fuel filter and ensure that it is not clogged; and the tank for rust. If there is rust in the tank i would take it to an auto radiator shop and have it cleaned and lined with either RedKote or POR.
There should be one fuel filter only, either the in-tank one or an external one designed specifically for gravity [not fuel-pump!] vehicles.
You may have to clean the carb. If crud got thru the filter it will be in the bowl/jets/whatever.
It is of no consequence which way the fuel inlet faces, as long as it is below the bottom of the fuel tank.
Do you have the factory service manual part number 99484-78?
Cleaning a Carb
1. Removing it from the bike should be straight forward. First thing when it is out is to check the pilot screw setting. Turn it all the way in until gently seated counting the number of 1/4 turns; then write this number down; then reset it.
2. I put mine in a vice to remove the screws, and for much of the following work. Wrap in a shop towel; close the vice gently taking extra care with the choke and throttle linkages. The vice is a needed extra pair of hands.
EDIT: A better choice than a plain vice ...
3. You must be very careful handling the float so as to not change the level. You must have the official specs for setting the level as in the FM, and check it, every time you dismantle the carb, as the last thing before putting it back together.
4. The jets are made of brass, a soft metal that is easily damaged. Use an exact correct size screwdriver. I ground a medium flat blade screwdriver down to exact size on my bench grinder to access the slow jet.
5. The general appearance of the inside of the carb is not necessarily a good indication of its condition. It can look spotless and have clogged jets, or look cruddy and have clear jets.
6. Clean each individual part. Do not allow any solvents to contact any rubber parts [tip of needle, o-ring seal for bowl]
7. Make a list of all of the jets and passages for your carb using the carb manual or the FM for the bike. Then ensure that you can blow either compressed air or carb cleaner thru each one.
8. Remove the pilot screw and clean the parts and the passage. The passage contains in this sequence: pilot screw, spring, washer, o-ring. These are very small parts, especially the washer and o-ring. Usually the spring will easily fall out. One time i thought the spring was not in there because it would not fall out; i obtained a new spring and could not get it in! The technique for removing the washer and o-ring is to use a pipe cleaner: stick it in the hole, twist it around, remove it - you should see the washer and o-ring on the end of the pipe cleaner.
EDIT: the washer and o-ring are part of the pilot screw assembly for 1979 on. They are not in the 1978 and earlier Keihin carbs.
Remember that the purpose of the washer is to protect the o-ring from the spring and you will always get them back in in the correct sequence.
9. Dismantle the accelerator pump assembly noting carefully the sequence and orientation of the parts. Clean and inspect the parts. Replace the diaphragm if it is cracked.
10. Check the float level then carefully put it back together. I personally find it very confusing trying to decide which way to bend the tang if it is not correct. If the fuel level is low is the float high or low? Do i need to bend the tang up or down? On the bench the carb is usually upside down, adding to the confusion. Sort all this out before making an adjustment.
Best to replace the original Phillips screws for the bowl with stainless steel socket head screws.
You should examine the in-tank fuel filter and ensure that it is not clogged; and the tank for rust. If there is rust in the tank i would take it to an auto radiator shop and have it cleaned and lined with either RedKote or POR.
There should be one fuel filter only, either the in-tank one or an external one designed specifically for gravity [not fuel-pump!] vehicles.
You may have to clean the carb. If crud got thru the filter it will be in the bowl/jets/whatever.
It is of no consequence which way the fuel inlet faces, as long as it is below the bottom of the fuel tank.
Do you have the factory service manual part number 99484-78?
Cleaning a Carb
1. Removing it from the bike should be straight forward. First thing when it is out is to check the pilot screw setting. Turn it all the way in until gently seated counting the number of 1/4 turns; then write this number down; then reset it.
2. I put mine in a vice to remove the screws, and for much of the following work. Wrap in a shop towel; close the vice gently taking extra care with the choke and throttle linkages. The vice is a needed extra pair of hands.
EDIT: A better choice than a plain vice ...
3. You must be very careful handling the float so as to not change the level. You must have the official specs for setting the level as in the FM, and check it, every time you dismantle the carb, as the last thing before putting it back together.
4. The jets are made of brass, a soft metal that is easily damaged. Use an exact correct size screwdriver. I ground a medium flat blade screwdriver down to exact size on my bench grinder to access the slow jet.
5. The general appearance of the inside of the carb is not necessarily a good indication of its condition. It can look spotless and have clogged jets, or look cruddy and have clear jets.
6. Clean each individual part. Do not allow any solvents to contact any rubber parts [tip of needle, o-ring seal for bowl]
7. Make a list of all of the jets and passages for your carb using the carb manual or the FM for the bike. Then ensure that you can blow either compressed air or carb cleaner thru each one.
8. Remove the pilot screw and clean the parts and the passage. The passage contains in this sequence: pilot screw, spring, washer, o-ring. These are very small parts, especially the washer and o-ring. Usually the spring will easily fall out. One time i thought the spring was not in there because it would not fall out; i obtained a new spring and could not get it in! The technique for removing the washer and o-ring is to use a pipe cleaner: stick it in the hole, twist it around, remove it - you should see the washer and o-ring on the end of the pipe cleaner.
EDIT: the washer and o-ring are part of the pilot screw assembly for 1979 on. They are not in the 1978 and earlier Keihin carbs.
Remember that the purpose of the washer is to protect the o-ring from the spring and you will always get them back in in the correct sequence.
9. Dismantle the accelerator pump assembly noting carefully the sequence and orientation of the parts. Clean and inspect the parts. Replace the diaphragm if it is cracked.
10. Check the float level then carefully put it back together. I personally find it very confusing trying to decide which way to bend the tang if it is not correct. If the fuel level is low is the float high or low? Do i need to bend the tang up or down? On the bench the carb is usually upside down, adding to the confusion. Sort all this out before making an adjustment.
Best to replace the original Phillips screws for the bowl with stainless steel socket head screws.
Last edited by IronMick; Apr 24, 2011 at 06:08 AM. Reason: sp
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fuel problems
Yep It is a butterfly carb, brandnew petcock, happened before so thats why i got the 90 deg barb. Only 1 in tank filter and i just lined the tanks. Sadly all i have is the clymers book. I have cleaned out the carb. I have fuel flowing out of the line when i disconect it from the carb but just dosent flow into the carb itself
I am wondering if it is a L76 to 78 or a 79 to 85 Keihin - the float setting is different between these. On the earlier ones the pilot screw and spring are exposed on the top of the carb; the later ones have it enclosed in a tube which was originally capped. Can you post some pics?
Either the float setting in incorrect or the fuel passage in the carb is blocked, in which case you could follow the carb cleaning notes i posted above.
Either the float setting in incorrect or the fuel passage in the carb is blocked, in which case you could follow the carb cleaning notes i posted above.
The 88 is the year either of a design change or of the first year it was used. The first year for the CV carb was 1989, so yours would be the newest version of the butterfly carb.
I believe the float setting should be 16 to 17 mm or .63 to .67 inch. This is the float setting in the factory service manual for the 79 to 85 butterfly carbs so it should be the same.
The float setting given in the Clymer is exactly the opposite of what is in the factory service manuals.
I believe the float setting should be 16 to 17 mm or .63 to .67 inch. This is the float setting in the factory service manual for the 79 to 85 butterfly carbs so it should be the same.
The float setting given in the Clymer is exactly the opposite of what is in the factory service manuals.
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Well I found the problem to be to much slack in the fuel line so I shortened it up and plenty of fuel....but hit the start button and turns over once then sounds like batt is dead but fully charged. I am thinking starter is seized now. How can I tell the difference in a presolite and hittachi starter? or does it matter?
From the parts catalogs the Hitachi starter motor was used from 1974 to early 1976. The Prestolitre was used from 1967 to 1980. I do not know how to describe the difference other than that. Post some pics and someone may know.
The difference does matter. I believe the mounting bolts are different.
The battery may be fully charged, but that does not mean that it is good, even if new. Use the following notes. Then if the battery really is good you should dismantle the starter motor, clean it up inside [it will be filthy in there!] using a toothbrush and a spray can of electrical contacts cleaner. When putting it back together use kitchen twist ties to temporarily hold the brushes in place.
It is a simple motor, relatively easy to dismantle etc.
Here are some notes ...
IronHead Charging System Checkout
You need a multimeter. The digital ones are best and can be had for less than $10.00. A voltmeter is a multimeter set to measure DC volts. An ammeter is a multimeter set to read DC current in amps. The ohmmeter section of the multimeter will test for continuity. Continuity means that current may flow between the two points.
I find alligator clip probes are much more convenient than pointer probes. Occasionally a pointer probe is better so i have a set of each.
When using a Multimeter, if the object fails a test, repeat the test ensuring that you have good connections with the meter probes, especially to a good ground.
1. Fully charge battery.
It is not good enough to put it on a charger overnight and assume it is fully charged. Some batteries will take 24 hours to fully charge. The way to know for sure is to do a specific gravity test [for liquid filled batteries], or to use an automatic battery charger.
I have heard that you should never use a battery charger greater than 2 amps for any motorcycle; that it is best to use between .75 and 1.5 amps. Best are the automatic chargers such as Battery Minder or Battery Tender.
2A. Cell test battery [not for maintenance-free batteries].
Remove caps from battery cells. Keep the red voltmeter lead on a terminal and insert the black lead progressively into each cell, far enough that it contacts the plates. You should get readings of 2, 4, 6, 8, 10 and 12 volts. If one cell does not contribute its proper 2 volts then that cell is dead and the battery is no good.
2B. Load test battery.
It is said that, with electronic ignition, you should never crank the engine without grounded plugs attached to the wires. For this test you should install an extra set of plugs into the wires and set them onto the top cylinder head fins.
Disconnect both spark plugs. Attach voltmeter leads to the battery terminals. Crank the engine for 10 seconds [no more!]. Observe the meter WHILE cranking. If it goes below 10 volts then the battery is no good. Alternatively you can buy an expensive battery load tester.
Bring the battery up to full charge again before proceeding.
3A. Current Drain Test #1
Disconnect the battery -ve cable from the battery. Connect the ammeter between battery -ve post and the battery cable. It should read .003 amps or less.
3B. Current Drain Test #2
Disconnect the +ve terminal from the battery. Connect an automotive test light between the battery and the cable. If light comes on there is a current draw.
Note: To determine which circuit is faulty disconnect the circuit breakers or remove the fuses one at a time. When the light goes out you know which circuit is the problem.
3C. Battery Cables Test
With voltmeter connected to battery terminals check voltage while cranking. Then with voltmeter on battery cables check voltage while cranking. If voltage drop due to cranking [should not go below 10 volts] is different cables may be bad or there may be corrosion.
Here is another very simple non complex test you can do if you suspect that something is draining your battery when the key is off. This applies to bikes that have no digital instrumentation (like ironheads). Unhook your negative battery terminal. Touch the wire back to the negative battery terminal, there should be no spark when you do. If it arks and sparks (like a downed hydro pole in a rain storm in a horror movie) then something is drawing power when it shouldn't be.
4. Charging System Test
Measure the battery voltage with the bike not running. It should be at least 12.x; preferably it will be 13.x.
Measure the voltage with the bike idling at about 2000 to 3000 RPM. It should be at least 1.0 volts higher than the not-running reading, otherwise the charging system is not charging the battery. It should be at least 13.x, preferably 14.x.
The difference does matter. I believe the mounting bolts are different.
The battery may be fully charged, but that does not mean that it is good, even if new. Use the following notes. Then if the battery really is good you should dismantle the starter motor, clean it up inside [it will be filthy in there!] using a toothbrush and a spray can of electrical contacts cleaner. When putting it back together use kitchen twist ties to temporarily hold the brushes in place.
It is a simple motor, relatively easy to dismantle etc.
Here are some notes ...
IronHead Charging System Checkout
You need a multimeter. The digital ones are best and can be had for less than $10.00. A voltmeter is a multimeter set to measure DC volts. An ammeter is a multimeter set to read DC current in amps. The ohmmeter section of the multimeter will test for continuity. Continuity means that current may flow between the two points.
I find alligator clip probes are much more convenient than pointer probes. Occasionally a pointer probe is better so i have a set of each.
When using a Multimeter, if the object fails a test, repeat the test ensuring that you have good connections with the meter probes, especially to a good ground.
1. Fully charge battery.
It is not good enough to put it on a charger overnight and assume it is fully charged. Some batteries will take 24 hours to fully charge. The way to know for sure is to do a specific gravity test [for liquid filled batteries], or to use an automatic battery charger.
I have heard that you should never use a battery charger greater than 2 amps for any motorcycle; that it is best to use between .75 and 1.5 amps. Best are the automatic chargers such as Battery Minder or Battery Tender.
2A. Cell test battery [not for maintenance-free batteries].
Remove caps from battery cells. Keep the red voltmeter lead on a terminal and insert the black lead progressively into each cell, far enough that it contacts the plates. You should get readings of 2, 4, 6, 8, 10 and 12 volts. If one cell does not contribute its proper 2 volts then that cell is dead and the battery is no good.
2B. Load test battery.
It is said that, with electronic ignition, you should never crank the engine without grounded plugs attached to the wires. For this test you should install an extra set of plugs into the wires and set them onto the top cylinder head fins.
Disconnect both spark plugs. Attach voltmeter leads to the battery terminals. Crank the engine for 10 seconds [no more!]. Observe the meter WHILE cranking. If it goes below 10 volts then the battery is no good. Alternatively you can buy an expensive battery load tester.
Bring the battery up to full charge again before proceeding.
3A. Current Drain Test #1
Disconnect the battery -ve cable from the battery. Connect the ammeter between battery -ve post and the battery cable. It should read .003 amps or less.
3B. Current Drain Test #2
Disconnect the +ve terminal from the battery. Connect an automotive test light between the battery and the cable. If light comes on there is a current draw.
Note: To determine which circuit is faulty disconnect the circuit breakers or remove the fuses one at a time. When the light goes out you know which circuit is the problem.
3C. Battery Cables Test
With voltmeter connected to battery terminals check voltage while cranking. Then with voltmeter on battery cables check voltage while cranking. If voltage drop due to cranking [should not go below 10 volts] is different cables may be bad or there may be corrosion.
Here is another very simple non complex test you can do if you suspect that something is draining your battery when the key is off. This applies to bikes that have no digital instrumentation (like ironheads). Unhook your negative battery terminal. Touch the wire back to the negative battery terminal, there should be no spark when you do. If it arks and sparks (like a downed hydro pole in a rain storm in a horror movie) then something is drawing power when it shouldn't be.
4. Charging System Test
Measure the battery voltage with the bike not running. It should be at least 12.x; preferably it will be 13.x.
Measure the voltage with the bike idling at about 2000 to 3000 RPM. It should be at least 1.0 volts higher than the not-running reading, otherwise the charging system is not charging the battery. It should be at least 13.x, preferably 14.x.
Last edited by IronMick; Apr 25, 2011 at 10:13 PM.
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I put my meter on before starting and got 12 volts. while trying to crank over, got 7 volts. This while everything is still intact. I will charge battery for 48 hrs then see what happens. I do believe it should still start by kicking unless im missing something? But I tried that route as well and still nothing.