Kawasaki KLR Forum banner

1 - 20 of 24 Posts

·
Premium Member
Joined
·
2,453 Posts
Discussion Starter #1
This is something I need to understand though I have never read a post about the carburetor float level and setting. I have read the Clymer manual but...
-how does the float level effect the engine?
-the float level is 17.5 mm or .69 in
-have you ever measured the float level height?
-have you ever adjusted the float level height?
-is there a maximum the float level can be adjusted?

Thanks for your input.
 

·
Administrator
Joined
·
8,365 Posts
This is something I need to understand though I have never read a post about the carburetor float level and setting. I have read the Clymer manual but...
-how does the float level effect the engine?
-the float level is 17.5 mm or .69 in
-have you ever measured the float level height?
-have you ever adjusted the float level height?
-is there a maximum the float level can be adjusted?

Thanks for your input.
The float level keeps enough fuel in the bowl to feed the engine. So, the only way for it to impact the engine is if the level is too low, which could serve to starve the engine of fuel in conditions where the engine is demanding lots of it. That would be pretty much WOT at high loads, like when you're trying to maintain 100mph, or up hill into a huge headwind.

I did measure the float level once, using a clear piece of plastic tubing attached to the drain and curled up towards the top of the carb. It was spot-on and didn't need to be adjusted.The fuel level should be sitting a bit higher that the joint between the carb body and the bowl.

There was a time when floats would leak (brass) or would soak up fuel and sink (plastic), but I haven't run into an issue like that in ages.

A more likely cause of incorrect level in the bowl, on the KLR, is a failure of the vacuum petcock - it won't flow fully and can't keep the bowl full. Unfortunately, you can't see that with a float level inspection, as the bowl will fill to the correct level by the time the engine is off.

A maximum? There is usually a tolerance on the setting, but there's nothing to be gained by setting the float level higher.

Tom
 

·
Registered
Joined
·
14 Posts
The float level is actually pretty important. If the float is set to high it can make the engine rich as there is less ground the fuel has to cover to get up through the emulsion tube, through the carb body and into your engine. A high float level can fill your air bleeds causing you to be on the incorrect fuel circuit for engine demands. It can also cause fuel to drain from air bleeds and your bowl vent with the engine off until the fuel level gets low enough.
A cool expirement to help understand this is to fill a glass with water. punch holes into the bottom quarter of a straw simulating an emulsion tube. The more holes you punch in the straw the more suction or vacuum is required to suck the water to your mouth, but if you put the end of the straw in the water enough to cover the holes it will do just the opposite and allow more water to your engine:) (mouth) with less suction resulting in a rich condition.
Mr. Smitz was right on about the low float!
 

·
Premium Member
Joined
·
2,453 Posts
Discussion Starter #4
The float level keeps enough fuel in the bowl to feed the engine. So, the only way for it to impact the engine is if the level is too low, which could serve to starve the engine of fuel in conditions where the engine is demanding lots of it. That would be pretty much WOT at high loads, like when you're trying to maintain 100mph, or up hill into a huge headwind.

I did measure the float level once, using a clear piece of plastic tubing attached to the drain and curled up towards the top of the carb. It was spot-on and didn't need to be adjusted.The fuel level should be sitting a bit higher that the joint between the carb body and the bowl.

There was a time when floats would leak (brass) or would soak up fuel and sink (plastic), but I haven't run into an issue like that in ages.

A more likely cause of incorrect level in the bowl, on the KLR, is a failure of the vacuum petcock - it won't flow fully and can't keep the bowl full. unfortunately, you can't see that with a float level inspection, as the bowl will fill to the correct level when the engine is off.

A maximum? There is usually a tolerance on the setting, but there's nothing to be gained by setting the float level higher.

Tom
I like your method of checking the float level. The manual shows to have the carburetor off the engine, bowl removed, and turned upside down. The measurement should be 17.5 mm. The adjustment is made my bending a tab that rests on the float valve. This is what I attempted a couple of months ago.
-The carburetor was removed from the engine.
-Measured the float height at 15.5 mm.
-Removed and bent the float adjustment tab (many times) until it was close to 17.5 mm.
-End result was the static float level was correct though the tab put enough pressure on the float valve that it closed the flow of fuel.

Is this the correct method to set the float level. If so, why did I run into the float valve problem?

I like your method of measuring the float level. What fitting did you use to replace the drain screw? What exterior mark on the carburetor did you use to check the float level?

"vacuum petcock" I can't find this in the Clymers manual.
 

·
Registered
Joined
·
1,333 Posts
Run a clear piece of tubing off the float bowl drain and loop it up along side the carb and tape it in place. Your reference mark for measurement will be where the bowl joins the carb body. Open the bowl drain screw and the fuel will flow into the tube showing you where the fuel level is at. It should be right at the the top of the bowl. No need to remove the drain screw.
 

·
Registered
Joined
·
14 Posts
I like your method of checking the float level. The manual shows to have the carburetor off the engine, bowl removed, and turned upside down. The measurement should be 17.5 mm. The adjustment is made my bending a tab that rests on the float valve. This is what I attempted a couple of months ago.
-The carburetor was removed from the engine.
-Measured the float height at 15.5 mm.
-Removed and bent the float adjustment tab (many times) until it was close to 17.5 mm.
-End result was the static float level was correct though the tab put enough pressure on the float valve that it closed the flow of fuel.

Is this the correct method to set the float level. If so, why did I run into the float valve problem?

I like your method of measuring the float level. What fitting did you use to replace the drain screw? What exterior mark on the carburetor did you use to check the float level?

"vacuum petcock" I can't find this in the Clymers manual.
When checking the float the carb can not be completely upside down. The float needle has a spring loaded rod in it that can't be depressed when making your adjustment. when you flip the carb upside down start to tilt it slowly with the needle at the top and the float towards the ground until the float stops. once it stops if you keep tilting you will see the float move a little more depressing the spring in the needle. If you adjust the float with this spring depressed it will be inaccurate.
Hope this helps solve your problem.
Also in my Kawasaki manual the petcock is called the fuel tap. I've also heard it called a cockpipe, and fuel valve. It has a vacuum line that attaches to the carb or intake so that even with the fuel valve in the "on" position it will stop flow with the engine off.
 

·
Premium Member
Joined
·
2,453 Posts
Discussion Starter #7
When checking the float the carb can not be completely upside down. The float needle has a spring loaded rod in it that can't be depressed when making your adjustment. when you flip the carb upside down start to tilt it slowly with the needle at the top and the float towards the ground until the float stops. once it stops if you keep tilting you will see the float move a little more depressing the spring in the needle. If you adjust the float with this spring depressed it will be inaccurate.
Hope this helps solve your problem.
Also in my Kawasaki manual the petcock is called the fuel tap. I've also heard it called a cockpipe, and fuel valve. It has a vacuum line that attaches to the carb or intake so that even with the fuel valve in the "on" position it will stop flow with the engine off.
Thanks RBW. Good explanation of how to adjust the static float level . Now I understand.

Thanks SLO. Good method. Can the float level be set too high or can the gasoline be seen higher (in the tube) than the float bowl line?
 

·
Registered
Joined
·
14 Posts
No problem Tim. In all actuallity your float was probably good, that spring could be the difference of 2mm! It very rarely comes out of adjustment without another issue happening.
 

·
Administrator
Joined
·
8,365 Posts
Tim

I think all your questions got answered.The process you described, and the plunger issue that RBW noted, are the reasons that I think the method of using a tube off of the bowl drain is the simplest and most accurate. Not matter what else is going on, it shows where the fuel level is. It should be a bit above the top of the bowl.

All KLRs have a vacuum operated petcock. With time, the innards can begin to die/malfunction, leaving you with no fuel flow and possibly stranded.

Blanking off the vacuum plate is an easy enough fix, though it takes some gentle fabbing and the right kind of gasket material.

The "vatrader upgrade" swaps out a standard petcock for less than $20. Less trouble than fabbing a blanking plate, IMO.

Tom
 

·
Premium Member
Joined
·
2,453 Posts
Discussion Starter #12
I knew what a vacuum petcock was but did not know what it had to do with the bowl level. Now I do.

My 2005 gave me surging issues from the beginning and I tried everything other than float level. One thing I found was the "crimping vacuum line" (caused by heat and time) though that did not resolve the issue.

2007 I went to Moab and met Chris Krok "BigCee". He helped me block off the petcock with a piece of fuel gasket. It worked well until he sent me one of his petcock kits. I now have the BigCee kit, vented gas cap, new fuel line, and proper needle position and jetting. Now I need to set the float level before the carburetor is installed. Problem is the 2005 is in San Diego. If I don't get another BigCee kit I will be buying the Yamaha manual petcock for the 2003.

Does the Yamaha petcock use the same O-ring as the KLR petcock?
 

·
Administrator
Joined
·
8,365 Posts
Does the Yamaha petcock use the same O-ring as the KLR petcock?
Tim -

The base is identical on the Yamaha petcock. It comes with the o-ring installed.

Tom
 

·
Registered
Joined
·
1,333 Posts
I knew what a vacuum petcock was but did not know what it had to do with the bowl level. Now I do.

My 2005 gave me surging issues from the beginning and I tried everything other than float level. One thing I found was the "crimping vacuum line" (caused by heat and time) though that did not resolve the issue.

2007 I went to Moab and met Chris Krok "BigCee". He helped me block off the petcock with a piece of fuel gasket. It worked well until he sent me one of his petcock kits. I now have the BigCee kit, vented gas cap, new fuel line, and proper needle position and jetting. Now I need to set the float level before the carburetor is installed. Problem is the 2005 is in San Diego. If I don't get another BigCee kit I will be buying the Yamaha manual petcock for the 2003.

Does the Yamaha petcock use the same O-ring as the KLR petcock?
Tim if you want to stop by on your way to San Diego I have heavy fuel resistant gasket material. Or I can mail you some.
 

·
Premium Member
Joined
·
2,453 Posts
Discussion Starter #15
Tim -

The base is identical on the Yamaha petcock. It comes with the o-ring installed.

Tom
Cool, it might fit the Gen1 KLR without cutting.
 

·
Registered
Joined
·
4 Posts
power loss issues

My 09 KLR recently began cutting out at high RPM. I have drained the tank, ran carb cleaner through it, cleaned the air filter, cleaned the muffler and it still won't rev beyond 3000 before stalling. I recently purchased a Clymer manual and read about the float being out of adjustment....I was about to pull the carb off but decided to check the overflow drain tube from the carb. I simply blew into it and sucked with a small amount of force. The tube gurgled a bit but seemed to have no restrictions. I then started the bike and to my suprise it ran perfect. I grabbed my helmet and took off for a test ride....after about 10 minutes of easy riding through gears and RPMs it still ran great but shortly after punching the throttle to climb a big hill it began cutting out again. I repeated the process of blowing and sucking into the overflow tube and it cleared once again allowing me to make it home without issue. Any clues as to what the underlying problem is and how to fix it? Thanks!
 

·
Registered
Joined
·
5,597 Posts
Could be occluded main jet.

If so, mere joy-juice application, "better living through CHEMISTRY," isn't likely to solve the problem.

Instead, a disassembly and manual cleaning is in order.

If you want to chance a fix with less effort, drop the float bowl and remove the main jet for cleaning.

If you're interested in how the KLR carburetor works, a good primer can be found by Googling, "Care And Feeding of the CVK40."

Sounds to me like you have a high-speed carburetor circuit problem, most likely a clogged main jet, diaphragm air leak (tear, puncture, or improper seal) a possibility.

Doubt you have a float-level problem. You may just have a piece of trash in the float bowl, occasionally honking up the works. Might be able to flush it out by draining the float bowl; tried that?
 

·
Registered
Joined
·
5 Posts
This is a few years late but it sounds like your gas cap is not breathing properly. It is creating a vacuum that will not allow enough fuel into the bowl fast enough at higher RPM's. I had the same issue around the same time as you did, but I was not on this forum at the time. I just opened the cap and rode like I didn't care. Everything was fine. I had to rebuild the cap and wallah, good to go.


My 09 KLR recently began cutting out at high RPM. I have drained the tank, ran carb cleaner through it, cleaned the air filter, cleaned the muffler and it still won't rev beyond 3000 before stalling. I recently purchased a Clymer manual and read about the float being out of adjustment....I was about to pull the carb off but decided to check the overflow drain tube from the carb. I simply blew into it and sucked with a small amount of force. The tube gurgled a bit but seemed to have no restrictions. I then started the bike and to my suprise it ran perfect. I grabbed my helmet and took off for a test ride....after about 10 minutes of easy riding through gears and RPMs it still ran great but shortly after punching the throttle to climb a big hill it began cutting out again. I repeated the process of blowing and sucking into the overflow tube and it cleared once again allowing me to make it home without issue. Any clues as to what the underlying problem is and how to fix it? Thanks!
 

·
Registered
Joined
·
5 Posts
For those of you reading this years after the original post, here is a great video showing how to adjust the CV carb's float when it is off the bike and the bowl is off. Super quick way to adjust it rather than testing with fuel, draining, taking the bowl off again, adjusting, and repeating that process.

Unfortunately I am unable to post a link until I've reached 15 posts so here is an un-linked url. Use this series of letters and numbers in a YouTube search box and the vid will pop right up ...


Float adjustment by Shane Conley

Below are the most important pieces of info from this thread, IMHO. Aside from removing the vacuum petcock and installing the aftermarket one that was mentioned by Tom Schmitz. You can get a the petcock at Eagle Mikes now so just go there and purchase one if you are tired of dealing with vacuum issues.

The float level is actually pretty important. If the float is set to high it can make the engine rich as there is less ground the fuel has to cover to get up through the emulsion tube, through the carb body and into your engine. A high float level can fill your air bleeds causing you to be on the incorrect fuel circuit for engine demands. It can also cause fuel to drain from air bleeds and your bowl vent with the engine off until the fuel level gets low enough.
A cool experiment to help understand this is to fill a glass with water. punch holes into the bottom quarter of a straw simulating an emulsion tube. The more holes you punch in the straw the more suction or vacuum is required to suck the water to your mouth, but if you put the end of the straw in the water enough to cover the holes it will do just the opposite and allow more water to your engine:) (mouth) with less suction resulting in a rich condition.
Mr. Smitz was right on about the low float!

I like your method of checking the float level. The manual shows to have the carburetor off the engine, bowl removed, and turned upside down. The measurement should be 17.5 mm. The adjustment is made my bending a tab that rests on the float valve. This is what I attempted a couple of months ago.
-The carburetor was removed from the engine.
-Measured the float height at 15.5 mm.
-Removed and bent the float adjustment tab (many times) until it was close to 17.5 mm.
-End result was the static float level was correct though the tab put enough pressure on the float valve that it closed the flow of fuel.

Is this the correct method to set the float level. If so, why did I run into the float valve problem?

I like your method of measuring the float level. What fitting did you use to replace the drain screw? What exterior mark on the carburetor did you use to check the float level?

"vacuum petcock" I can't find this in the Clymers manual.
When checking the float the carb can not be completely upside down. The float needle has a spring loaded rod in it that can't be depressed when making your adjustment. when you flip the carb upside down start to tilt it slowly with the needle at the top and the float towards the ground until the float stops. once it stops if you keep tilting you will see the float move a little more depressing the spring in the needle. If you adjust the float with this spring depressed it will be inaccurate.
Hope this helps solve your problem.
Also in my Kawasaki manual the petcock is called the fuel tap. I've also heard it called a cockpipe, and fuel valve. It has a vacuum line that attaches to the carb or intake so that even with the fuel valve in the "on" position it will stop flow with the engine off.
 

·
Premium Member
Joined
·
6,822 Posts
I still watched the whole video Tom. Thanks.
 
1 - 20 of 24 Posts
Top