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I have an 85 KLR and when it is cold it takes about 10 kicks to get it started. Once warm it starts right back up. it runs great through the first half of the throttle range but when the throttle is advanced beyond that the bike bogs down and starts to slow. This happens in every gear. I pulled the carb to clean it but when i opened it up the bowls looked clean as well piston/main chamber. I did not unscrew or remove anything beyond that because everything looked spotless. After that I checked the air filter which was clean and i ensured the carb was sealed tight on both sides. Any thoughts on what to check? Should I dive deeper into the carb or is that going to be a waste of time which i probably will mess up trying to put back together with the same exact settings as before? :46:

Thanks,

Jason
 

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I have an 85 KLR and when it is cold it takes about 10 kicks to get it started. Once warm it starts right back up. it runs great through the first half of the throttle range but when the throttle is advanced beyond that the bike bogs down and starts to slow. This happens in every gear. I pulled the carb to clean it but when i opened it up the bowls looked clean as well piston/main chamber. I did not unscrew or remove anything beyond that because everything looked spotless. After that I checked the air filter which was clean and i ensured the carb was sealed tight on both sides. Any thoughts on what to check? Should I dive deeper into the carb or is that going to be a waste of time which i probably will mess up trying to put back together with the same exact settings as before? :46:

Thanks,

Jason

Valves need adjusted.
 

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Thanks, I will give that a try. Is that something I can do by referencing a service manual or should I have someone smarter than me do it???
 

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Hi Jason, welcome to the forum. Keep in mind we don't have the benefit of hearing, smelling licking or feeling that you have being there on site. So some suggestions are helpful shots in the dark. And this just might be one right here. I'd suggest you run a therapeutic dose of carburetor cleaner through there before I wrenched anything. You might have a bit of carbon blocking or varnish buildup out of sight in the carb. A number of snake oils will do the trick if this is the issue. Sea Foam is the current favorite. Chevron Techron Concentrate Plus Fuel System Cleaner rates high in my book. Berryman B-12 Chemtool® Carburetor Fuel Injector and Fuel System Cleaner is another snake oil that has worked well for me. Most of these can be found at WalMart or your auto parts supply house. The instructions on the containers of these chemicals will suggest a maintenance dosage.....I'd be adding a therapeutic dosage. Let it marinate in a 50 / 50 mix a while. Start, run the rpm's up and down and let sit some more.

Another possibility [and there could be 40 possibilities] is a diaphragm issue on the slide. Might want to pull the top cap off the carb and check the condition of the diaphragm if the snake oil does not straighten things out. Classic symptom of problems with the diaphragm is a stumble coming off the slow jet circuit.
 

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Discussion Starter #5
update

Ok, so I decided to try the simple solution first and bought some Sea Foam. Added a large amount to tank and let it run for a bit/ then let it sit over night. then ran it some more.--------Bike starts up after a few kicks when cold now, also now, when i go to give the bike full throttle it still starts to bog down but then it works it's way through it and will give me full power...:) ........however, when i work through the bog and get the full power, the bike stalls out when that power is brought back out. When this happens it is very tough to start back up, 10-15 min and a bruised foot kinda hard. Does it sound like I just need to give the sea foam more time,,? is there anything i can do to help the process? or does it sound like something else may be wrong too????
 

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Ok, so I decided to try the simple solution first and bought some Sea Foam. Added a large amount to tank and let it run for a bit/ then let it sit over night. then ran it some more.--------Bike starts up after a few kicks when cold now, also now, when i go to give the bike full throttle it still starts to bog down but then it works it's way through it and will give me full power...:) ........however, when i work through the bog and get the full power, the bike stalls out when that power is brought back out. When this happens it is very tough to start back up, 10-15 min and a bruised foot kinda hard. Does it sound like I just need to give the sea foam more time,,? is there anything i can do to help the process? or does it sound like something else may be wrong too????
Have you drained the float bowl on the carburetor? Water will collect in there, and that will give you headaches. To me, if you found improvement with Sea Foam, you may just have some buildup in the carburetor rather than a mechanical failure somewhere. I would drain the float bowl and add a strong dose of snake oil by adding it into the carburetor through the fuel line. Disconnect the fuel line at the petcock and coax a straight dose of cleaner into the carburetor. Reconnect fuel line and try the run / soak cycle again. if that doesn't clear the issue up, you may need to go in and remove and clean the jets. I've done a number of cleanings without removing the carburetor from the bike. Cleaning is not that difficult. Here is a bottom view of the carburetor after removing the float bowl and float.



 

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Discussion Starter #7
I did drain the bowl about a week ago. I will try adding some cleaner straight to the fuel line. If that doesn't work I will pull the carb back apart. Thanks for the pics, those make for an excellent reference!
 

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What is this and where does it go?

Decided to take the carb apart and when i pulled out the floats this piece was just rattling around in there....Anybody know what this is and where do i put it?

Thanks
 

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Decided to take the carb apart and when i pulled out the floats this piece was just rattling around in there....Anybody know what this is and where do i put it?

Thanks
That would be your float valve.




 

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Discussion Starter #11
Carb is cleaner than new, still same problem.

Ok, so after trying some sea foam, i took the carb back out and pulled every last piece off of it and cleaned it till it was as clean as a carb can get. absolutely no gum/tar dirt or water. everything was put back together properly. The bike is still doing the same stinking thing though. Starts right up now after 1 or two kicks but regardless of weather it is hot or cold it bogs right down when you try to advance the throttle beyond the 50% mark weather you do it slow or quick. I can power through the bogg down and the bike will accelerate hard to normal rpms/ power/ etc...but then after 15 sec or so it will start to bogg back down and eventually stall......then it is a biiiiiiiizzzzznattch to start back up. I am at a complete loss here. Any and all suggestions please:46:
 

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What condition is the diaphragm in? Seated properly? If it has a puncture, tear, rip, hole, etc, the engine will stumble on acceleration. If the outer lip of the diaphragm is not seated in the groove of the carburetor, it is not functioning properly.
 

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Discussion Starter #13
Diaphragm is in excellent condition. I think it had to of been replaced in the past couple years it looks brand new. I took extra special care to make sure it was seated properly.
 

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Ok, so after trying some sea foam, i took the carb back out and pulled every last piece off of it and cleaned it till it was as clean as a carb can get. absolutely no gum/tar dirt or water. everything was put back together properly. The bike is still doing the same stinking thing though. Starts right up now after 1 or two kicks but regardless of weather it is hot or cold it bogs right down when you try to advance the throttle beyond the 50% mark weather you do it slow or quick. I can power through the bogg down and the bike will accelerate hard to normal rpms/ power/ etc...but then after 15 sec or so it will start to bogg back down and eventually stall......then it is a biiiiiiiizzzzznattch to start back up. I am at a complete loss here. Any and all suggestions please:46:

The bike ran good before yes? So something has changed. It's starting to sound like an electrical problem. Carry a spare spark plug and when the bike dies pull the spark plug cap and use the spare to check for spark. Might be hard to kick it and keep the plug grounded.

Did you ever check the valves? Doesn't sound like typical symptons but worth a look.

Another idea... might have and airleak on the intake side. While the bike is idleing spray some starter fluid, carb cleaner, or brake cleaner around the carb airbox junction and the carb cylinder junction. If the motor surges there's an airleak in the area. Also spray around the base of the cylinder.
 

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I still think you have a fuel problem.

I would check to see if the tank vents are clear. You can open the gas cap and see if it bogs down. You might want to try this with only half tank of fuel.
Blow air threw the vents on the tank and check your tank vent lines.

It could also be that the float it self is cutting the fuel flow before the bowl is full enough to run the motor threw all the ranges.
When you accell. you have fuel in the bowl, as the bowl empys it can not re supply fuel fast enough so it dies. After a short time it starts again because the bowl fills again. The harder you accell the quicker the bowl emptys.

You could try raising the float a bit more to raise the fuel level in the bowl.
Like I said before, make sure your tank is venting real well.

Kurt
 

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Discussion Starter #16
Well, i purchased the bike a couple months ago. When i bought the bike i test rode it on some tight trails behind the guys house so i never advanced the throttle beyond half way..very dumb of me. When i drove the two hours home and took the bike out, i noticed the problem. So it has always done this for me...... Checked the spark plug and it is getting a spark (ouch). I havn't checked the valves yet just because i wanted to try everything else before opening the engine up. (Not a mechanic here). --I am going to try the carb spray idea to check for leaks...the seals are old and i dont have alot of faith in them. I am also going to check the fuel tank vent line as well. ---if neither of these things yield any results i will pull the carb back out for about the 12th time now and try adjusting the floats.----if you have the carb sitting on its top with the bottom facing up which way would that be for the float adjustment---would i bend it towards the body of the carb????---thanks
 

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Well, i purchased the bike a couple months ago. When i bought the bike i test rode it on some tight trails behind the guys house so i never advanced the throttle beyond half way..very dumb of me. When i drove the two hours home and took the bike out, i noticed the problem. So it has always done this for me...... Checked the spark plug and it is getting a spark (ouch). I havn't checked the valves yet just because i wanted to try everything else before opening the engine up. (Not a mechanic here). --I am going to try the carb spray idea to check for leaks...the seals are old and i dont have alot of faith in them. I am also going to check the fuel tank vent line as well. ---if neither of these things yield any results i will pull the carb back out for about the 12th time now and try adjusting the floats.----if you have the carb sitting on its top with the bottom facing up which way would that be for the float adjustment---would i bend it towards the body of the carb????---thanks

Ahh...

Motorcyle carbs work on throttle position, here's a page with good info. When you have the throttle much more than about 1/2 way open you are on the main jet circuit.

It sounds like the main jet is too big and it's drowning out the motor. That's why the bike is bogging, too much fuel. That's why it's hard to start afterwards too the plug is wet. If the float level was too low it will be like running out of gas, sudden loss of power not a bog.
 

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Ahh...

Motorcyle carbs work on throttle position, here's a page with good info. When you have the throttle much more than about 1/2 way open you are on the main jet circuit.

It sounds like the main jet is too big and it's drowning out the motor. That's why the bike is bogging, too much fuel. That's why it's hard to start afterwards too the plug is wet. If the float level was too low it will be like running out of gas, sudden loss of power not a bog.
This is the problem when we can not see and hear the problem.
Bogging can mean different things to different folks.
Pull the plug and see what it looks like. If it is real dark or black it's getting to much fuel. If it's clean or has a very light tan brown color it's could be real lean.
To raise the float level you want the float to close the float needle when it raises higher in the bowl. Pulling the plug to see what it looks like should help reading the problem.

Kurt
 

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This is the problem when we can not see and hear the problem.
Bogging can mean different things to different folks.
Pull the plug and see what it looks like. If it is real dark or black it's getting to much fuel. If it's clean or has a very light tan brown color it's could be real lean.
To raise the float level you want the float to close the float needle when it raises higher in the bowl. Pulling the plug to see what it looks like should help reading the problem.

Kurt

Yea you're right about the plug.

I think the key to this is that the bike is hard to start after the "bogging". Open up the float bowel drain after it dies and see if there's gas in there.

With a bike this old and in unknown condition I would put every thing I could back to a stock conditon; carb jets, valves, timing, vacuum lines, etc. and go from there.
 

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Ok. So i pulled the plug and it was very wet. I think it looks a little black...(Picture attached). when i pulled the carb the bowl had tons of fuel in it. I am not sure if the jets are the original or not. I have attached a pic of the bottom of the carb with an arrow pointing to what i believe is the main jet (correct me if i am wrong please i just took an educated guess) The jet has "112" written on it. I have no idea if this is the factory size or not... What would be the next size smaller I would want to try out?--please note this is a klr250.
 

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