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Discussion Starter · #1 ·
My carbs never used to flood. I have new float needles and seats. They flood now that i installed the new needles and seats i just want to be sure its not the float height somehow before i order different needles and seats.

Yes i understand there is a procedure to get wet float height which i dont have the patience for that but i know people also do it on the bench.

28 mm carbs on a 98 royal star tour deluxe 1300.

Thanks
 

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Super Moderator "Loose Nut" - Houston, Texas
2001 Vstar 1100 Classic (sold), 2006 HD Electra Glide Ultra Classic
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should be between 8 to 9 mm

 

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Super Moderator "Loose Nut" - Houston, Texas
2001 Vstar 1100 Classic (sold), 2006 HD Electra Glide Ultra Classic
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When you are bench setting the floats with carbs upside down. So the higher you set them, the lower the level will be in the bowl when you turn carb right side up.
 

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Discussion Starter · #5 ·
When you are bench setting the floats with carbs upside down. So the higher you set them, the lower the level will be in the bowl when you turn carb right side up.
So another words if I take a measurement upside down and measure from The Mating surface to the top of the float let's say it reads 14 that would be an extremely low fuel level in the bowl if I understand you correctly?
 

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Super Moderator "Loose Nut" - Houston, Texas
2001 Vstar 1100 Classic (sold), 2006 HD Electra Glide Ultra Classic
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Correct.
 

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Discussion Starter · #7 ·
Are you sure that's correct the one cylinder or car if I should say that is not flooding has a float height of about 7 1/2 millimeters the other three are around the twelve and those are the three that are flooding to further conclude that my needles and seats are not leaking I did an air cast with just the weight of the float pushing the needle down while upside-down forcing air into the fuel chamber and there are no air leaks
 

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Super Moderator "Loose Nut" - Houston, Texas
2001 Vstar 1100 Classic (sold), 2006 HD Electra Glide Ultra Classic
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On all the carbs I've done on bench, yes. The higher the float with carb upside down, the lower it will be when right side up.
 

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Discussion Starter · #9 ·
On all the carbs I've done on bench, yes. The higher the float with carb upside down, the lower it will be when right side up.

So youre saying these average numbers will cause low fuel in the bowl?
Is this the correct way to place the carbs?
Which tang do i bend? The one the needle sits on?
If this is the correct bench position and these numbers would cause low fuel in the bowl to barely reach the pilot jet, how are they then flooding? All passages are clear, i used compressed air to test the floats to make sure they dont leak. I even tested all 4 floats in almost boiling water and they all float and do not push out air bubbles when submerged. Im stumped.
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Super Moderator "Loose Nut" - Houston, Texas
2001 Vstar 1100 Classic (sold), 2006 HD Electra Glide Ultra Classic
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There are several good videos out the that might assist you. Google, Float adjustment on CV carb. This is definitely a time where a picture is worth a thousand words, and I type slow. 🤣

 

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Discussion Starter · #11 ·
There are several good videos out the that might assist you. Google, Float adjustment on CV carb. This is definitely a time where a picture is worth a thousand words, and I type slow. 🤣

Right, but ive seen that video years ago amd its a harley carb. Harley also uses bench technique and yamaha does not, not to mention most carbs are different in design.

Hard to believe as popular as theses bikes are, google has turned up zero information almost like im the only one who has sought the info im looking for which i know is completely untrue.
 

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Super Moderator "Loose Nut" - Houston, Texas
2001 Vstar 1100 Classic (sold), 2006 HD Electra Glide Ultra Classic
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I bench set floats on all carbs. The process is similar on all. You must make sure float valve spring is operating correctly. When adjusting I bend tab close to float itself. The further away from valve you bend you adjust smaller amounts due to the length of arm. With float valve spring in good operating condition I've never had an issue bench adjusting floats. Remember, the smallest bend makes a huge change in level. Have you inspected the rubber end of float valve?
 

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Discussion Starter · #13 ·
I bench set floats on all carbs. The process is similar on all. You must make sure float valve spring is operating correctly. When adjusting I bend tab close to float itself. The further away from valve you bend you adjust smaller amounts due to the length of arm. With float valve spring in good operating condition I've never had an issue bench adjusting floats. Remember, the smallest bend makes a huge change in level. Have you inspected the rubber end of float valve?
Its new seats and needles. I forced air in through the fuel line amd they did not leak with just the weight of the float not even compressing the spring/shock absorber on the end of it.

Besides clogged pilot jet and bad needle seat what else can cause this?

I adjusted the floats to 8.5mm, reinstalled amd its still flooding like crazy.

Im about ready to sell this bike amd let someone else deal with the headache of carburetors
 

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Discussion Starter · #14 ·
I came across a post
I bench set floats on all carbs. The process is similar on all. You must make sure float valve spring is operating correctly. When adjusting I bend tab close to float itself. The further away from valve you bend you adjust smaller amounts due to the length of arm. With float valve spring in good operating condition I've never had an issue bench adjusting floats. Remember, the smallest bend makes a huge change in level. Have you inspected the rubber end of float valve?
I came across this

How to: Set Carburetor Float Height (BDS26 & BDS28) - XJRider.com.

For mikuni bds28mm carbs the float height at bench is 11 to 13mm.

This is why i cant find purposeful info.
Anyone else care to chime in?
 

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Super Moderator "Loose Nut" - Houston, Texas
2001 Vstar 1100 Classic (sold), 2006 HD Electra Glide Ultra Classic
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I can feel your frustrations. Might want to read the thread you linked again. Screenshot from your link for US model ( your location info says US), 6.2 to 8.2 mm.

107130


For Europe and Canada, 11 - 13 mm.

107131


My info states 8-9mm, which I resently used to set float level for a friend's bike:


107132


I bench set the floats at 9mm on my friend's bike. Living in Houston with our heat and understanding that fuel expands I went with the higher bench setting. He's been on the road for several years without an issue. I know it seems I'm the only one giving input, but there are probably only a few folks here that have messed with this bike carb float level. I'm not a professional carb builder, but have built 100s. Not saying I'm right, just expanding upon what I've had work for me. Good luck and please keep us informed on you progress.
 

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The o-ring around the needle seat can leak causing flooding.
Plugged pilot or main jets will not cause flooding, they will cause a lean condition.

Once you have set the float heights position the carbs upright as they would sit on the engine and with a remote tank of some sort apply fuel to them.
Let them sit for a few minutes and see if they leak fuel. If they do then the needles for some teason aren't shuuting off fuel when the bowls are at the correct level.

Blocked atmospheric vents will cause poor fuel level control and cause the bike to run poorly.

Are you sure it's flooding?
Are the plugs excessively wet with fuel or do you see black smoke at the exhaust pipes?
 

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Discussion Starter · #17 ·
The o-ring around the needle seat can leak causing flooding.
Plugged pilot or main jets will not cause flooding, they will cause a lean condition.

Once you have set the float heights position the carbs upright as they would sit on the engine and with a remote tank of some sort apply fuel to them.
Let them sit for a few minutes and see if they leak fuel. If they do then the needles for some teason aren't shuuting off fuel when the bowls are at the correct level.

Blocked atmospheric vents will cause poor fuel level control and cause the bike to run poorly.

Are you sure it's flooding?
Are the plugs excessively wet with fuel or do you see black smoke at the exhaust pipes?
Fuel is pouring into the intake through the main jets/needle jet at idle. Black smoke too especially on the left side of bike exhaust pipe. And by atmospheric vents you mean the two overflow hoses one on either side of carb banks /left and right then no. I blew through the fuel line to each side of carbs with only the weight of the floats pushing down but not compressing the springed shock absorber on the float needle itself and did not get air through them so i figure if air is not getting by the needle its not getting by the o ring on the seat. Each float is set at 8.5 mm upside down with the weight of the float only i just did this today amd its still flooding. When i say flooding, its like the throttle is wide open coming out the main jets at idle.
 

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Another thing to try:
With the bowls off and catbs upside down, connect a fuel line on and feed them fuel and look for fuel leaking in somewhere.

If all 4 needles seal up when closed then l would be looking for a reason they could be held open when fully assembled. e.g. a float that doesn't float, a binding float hinge or a misshaped or bent float that cant swing due to interference with something in its chamber or too much fuel pressure.

Not positive but l think the fuel pumps used in those are internally regulated, sometimes a failing pump can make too much pressure and cause this kind of problem.
Try running a fuel line ftom the petcock straight to the carbs and see if the problem persists.

I removed the pump from my Roadie years ago and have been gravity feeding it fuel without any problems.
 

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Discussion Starter · #19 ·
Another thing to try:
With the bowls off and catbs upside down, connect a fuel line on and feed them fuel and look for fuel leaking in somewhere.

If all 4 needles seal up when closed then l would be looking for a reason they could be held open when fully assembled. e.g. a float that doesn't float, a binding float hinge or a misshaped or bent float that cant swing due to interference with something in its chamber or too much fuel pressure.

Not positive but l think the fuel pumps used in those are internally regulated, sometimes a failing pump can make too much pressure and cause this kind of problem.
Try running a fuel line ftom the petcock straight to the carbs and see if the problem persists.

I removed the pump from my Roadie years ago and have been gravity feeding it fuel without any problems.
Another thing to try:
With the bowls off and catbs upside down, connect a fuel line on and feed them fuel and look for fuel leaking in somewhere.

If all 4 needles seal up when closed then l would be looking for a reason they could be held open when fully assembled. e.g. a float that doesn't float, a binding float hinge or a misshaped or bent float that cant swing due to interference with something in its chamber or too much fuel pressure.

Not positive but l think the fuel pumps used in those are internally regulated, sometimes a failing pump can make too much pressure and cause this kind of problem.
Try running a fuel line ftom the petcock straight to the carbs and see if the problem persists.

I removed the pump from my Roadie years ago and have been gravity feeding it fuel without any problems.
I put the original floats to the 1st set of carbs in that i never adjusted and i also put the original needles and seats in from my second set of carbs(im using my 2nd set of carbs because i cant use the original carbs to the bike due to a pms screw that i am unable to extract on one carb hence the need for the second set of carbs i have). The fuel coming out of two needle/main jets is less.

So, i am curious if it may actually be a faulty set of needles and or seats which i have another new rebuild kit coming tomorrow for me to install. I also have a hunch that maybe some type of air passage in the affected carbs is blocked, is there se type of schematic or picture(s) that show me what passages do what and which ones could also cause the rich condition with fuel coming out of the main jet/needle jet?

For Shits and giggles i also reinstalled the original fuel pump to the bike last night, he owner said it was causing the sputtering issue when i bought the bike bike that was not the issue at all it was a faulty ignition switch. I still have the same issue.

One other thing i noticed last night is the original floats to the second set of carbs is around the 11.5 mm mark. I measured with them upside down and also when they were tilted and had just seated the needles. I also blew into the fuel passages on both banks of carbs and could not hear any air coming through when seated with just the weight of float without compressing the shock absorber on top of the needle as i have done when i set the other floats to 8.5 mm which @lesblank said the float should be between 8 and 9mm. It boggles my mind that i have less fuel coming out of the affected carbs main jets/needle jets with a lower fuel level in the bowls and if it really is the needles and or seats, why can i not get air passed them when i test to see if they leak? Im baffled. So if someone can show me what passages to look at that could be clogged causing my issue id appreciate it and would be willing to pay for the knowledge to actually fix my bike. Im bummed out cant ride two wheels and the weather has been fantastic.
 

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Do you have a way to test fuel pressure?
Have you tried bypassing the fuel pump?
Doubtful that you have 4 defective neddle/seats, l could see one but not all 4.
 
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