[TrialsRider]

Mikuni carbs have excellent service documentation online free, sudco is a company name sometimes associated. The float height is specified in the motorcycles service manual because it is determined by the angle the carbs set on the bike as much as anything else. Usually very close to half way through the floats limit of travel it should stop flow of fuel.

Float level is critical because it makes a thing called the emulsion tube work well or not. The emulsion tube introduces bubbles into the fuel and starts the fuel atomization process.

 

[HipsterSquid]

He said it leaks while "running" that indicates that the petcock is only flowing while vacuum is applied therefore working properly. Dont go tearing the carbs apart again just yet, The problem may be much simpler. Remove the drain screws and inspect the tips. If they look like this:

Chuck them in a drill and spin them on a file until they seal properly. I suspect this is your problem because if the floats were too high you'd be complaining about your cylinders flooding and other poor running issues.

 

[Bobby05]

He said it leaks while "running" that indicates that the petcock is only flowing while vacuum is applied therefore working properly. Dont go tearing the carbs apart again just yet, The problem may be much simpler. Remove the drain screws and inspect the tips. If they look like this: View attachment 106756
Chuck them in a drill and spin them on a file until they seal properly. I suspect this is your problem because if the floats were too high you'd be complaining about your cylinders flooding and other poor running issues.

How will I know when I should stop filing them so they seal properly before putting them back on the carbs

 

[TrialsRider]

How will I know when I should stop filing them so they seal properly before putting them back on the carbs

inspect to see if the screws are mangled like that first.

 

[HipsterSquid]

They need to look like this when your done:

 

[Bobby05]

They need to look like this when your done: View attachment 106757

Alright I’ll give it a shot

 

[DesmoDog]

Somewhere there's a guy who had to determine the tolerances for that part. And there's someone else who had to test things to make sure they worked. And someone else who had to determine the capability of the process to manufacture the part to those tolerances. And someone else who had to check to make sure the finished part met the numbers on the drawing.

And then there's the guy who puts it in a drill and files it until it looks right.

Not criticising, do whatever works. I just find it funny (having been the guy who had to develop/check tolerances on things for a lot of years)

 

[Bobby05]

They need to look like this when your done: View attachment 106757

So I finally have the time to do it now and where is the drain screw you’re talking about because the one on the bottom of the bowl looks nothing like that

 

[HipsterSquid]

So I finally have the time to do it now and where is the drain screw you’re talking about because the one on the bottom of the bowl looks nothing like that

Post a pic of your carbs

 

[HipsterSquid]

Somewhere there's a guy who had to determine the tolerances for that part. And there's someone else who had to test things to make sure they worked. And someone else who had to determine the capability of the process to manufacture the part to those tolerances. And someone else who had to check to make sure the finished part met the numbers on the drawing.

And then there's the guy who puts it in a drill and files it until it looks right.

Not criticising, do whatever works. I just find it funny (having been the guy who had to develop/check tolerances on things for a lot of years)

The tolerance on a drain screw is not critical. It's threaded, and it's soft. So as long as it's circumference is fairly uniform.... it will seal.

 

[TrialsRider]

So I finally have the time to do it now and where is the drain screw you’re talking about because the one on the bottom of the bowl looks nothing like that

Determine the model # of your carburetors and then google up a part list and/or exploded diagram of that make & model carburetor. That is how you find out what is in there without even taking it apart.

 

[Spyder13]

TheGSResouces.com

 

[TrialsRider]

Found it for you: http://www.mikunipower.com/catalog/mikunicarburetorcatalog2012.pdf
page 12

 

[Bobby05]

Found it for you: http://www.mikunipower.com/catalog/mikunicarburetorcatalog2012.pdf
page 12

So decided to replace the floats to see if that would help and it didn’t, I do have them to spec but it still over flows out the lines at a constant rate.

One thing I thought of but it might not matter is I don’t have an inline fuel filter, could the gas be coming out of the tank to quickly

 

[CaTacL1sm]

My money is on something causing the float needle not to seat. does fuel overflow out of all carbs or just one?

 

[Bobby05]

My money is on something causing the float needle not to seat. does fuel overflow out of all carbs or just one?

So there’s four carbs, it leaks from the far left, middle left and sometimes the middle right

 

[TrialsRider]

So it's bad on the side where the side stand is, nothing new there, the #1 carb evaporates last, it has the most solids and corrosion in it.

 

[TrialsRider]

... could the gas be coming out of the tank to quickly

That's what the carburetor float valve is for. It needs to seal off the flow and regulate it at the correct height, just like a toilet tank. It can do that because there is such a small opening the needle valve takes very little force to close off the flow and that force is flotation of the floats. It also takes very little dirt to plug a needle valve or make it leak, it needs to run clean fuel.

 

[Bobby05]

That's what the carburetor float valve is for. It needs to seal off the flow and regulate it at the correct height, just like a toilet tank. It can do that because there is such a small opening the needle valve takes very little force to close off the flow and that force is flotation of the floats. It also takes very little dirt to plug a needle valve or make it leak, it needs to run clean fuel.

I’m gonna take them apart and clean them again and put a fuel filter in

I also plan on taking the bike to a shop on Saturday

 

[CaTacL1sm]

I highly recommend ultrasonically cleaning them