Thursday, September 12, 2013

Kawasaki KLR 250 Carb Cleaning Information

Bottom View of the KLR 250 CVK34 carburetor showing the main and pilot jetsIf you were to browse any KLR250 related forum the most common ailment youd hear owners complain about is some type of starting or running problem, usually carburetor related. These problems arent biased to just the KLR, any carbureted bike can experience them. Theyre usually due to dirt in the fuel clogging a jet, or varish gumming everything up. The only solution is to remove the carb from the bike and give it a thorough cleaning and inspection. Thats what this article is meant to do, show you the basics of the KLR250 carburetor and give a quick run through on how to clean it.We wont get into how a carb works, but if youre interested in learning more check out The Care and Feeding of the Keihn Carb.

Kawasaki KLR 250 carburetor diagram cvk34The KLR 250 comes with a Keihn CVK34 carburetor. Dont let the parts diagram to the left fool you, CVK34 is a very simple design. To clean the carb youll need to remove it from the bike. Probably one of the more painful processes whenever you have to work on your bikes carb is trying to get it out of the bike. At the very least itll require removing the side plastics, seat, and fuel tank, though we have found that unbolting the exhaust muffler and the top bolts of the subframe (the part the seat bolts to) make things easier by allowing you to pivot the entire subframe backwards giving better access to the carb. Once youve gotten to the carb follow these steps to disconnect and remove it.

1. Turn off the fuel petcock on the fuel tank
2. Place a container under the fuel drain hose. That is the hose which leads from the fuel drain screw to just in front of the rear wheel.
3. Open drain screw, located on the bottom right side of the carb (on the float bowl) and allow all of the fuel to drain from the carb.
4. Remove the fuel line from the left side of the carb (black rubber line from the fuel tank)
5. Remove the throttle cables, one screw holds the bracket in place.
6. Carefully unscrew the plastic choke cable nut from the left side of the carburetor. This is where the choke cable screws into the carb. The plastic nut is very fragile so be careful!
7. Loosen the clamp on the front side of the carb holding it to the engine.
8. Remove the rear carb to airbox tube

OK now you should have the carb out of the bike and holding it in your hands. Next step is tearing it down while being very careful not to lose or damage anything in the process.

KLR 250 Carburetor Picture PhotoTeardown:
1. Remove the four screws on the plastic piece on the top of the carb. Underneath there should be a diaphragm, spring, slide, needle and white piece of plastic. Make a mental note of the order of those parts (slide, needle, white plastic piece, spring) and remove them. Be careful not to tear the rubber diaphragm.
2. Remove the float bowl. That is the metal bowl on the bottom of the carb, held in place with four screws. Be careful when removing it as the float and needle valve can fall out. Make a note of the position of the float and needle and remove them.
3. Next step is to unscrew the main and pilot jets from the carb body. (see diagram above for their location)

Pilot Screw Info:
The KLRs carb has a pilot mixture screw which controls the amount of fuel that enters the engine while at idle. However to stop owners from fiddling with it Kawasaki covered the screw with a small tin cap. The only way to get to this screw is to carefully drill a small hole in the tin cap and then pry it off with a small screw driver. The utmost care must be taken so you dont screw all of the way through to the pilot screw itself. Once the screw is accessible then you can remove it. There should be an o-ring, washer, and spring on the end of it, note their order and set them to the side.

Thats about all you need to disassemble. Wasnt that hard was it? Now its time to clean everything. Just about everyone has their own way of doing this but what we suggest is buying a few bottles of carb cleaner (the kind you pour in your cars fuel tank) and a couple cans of spray type carb cleaner that have the small plastic tubes on them. Fill a small container with the carb cleaner (bottle type) and soak all of the metal parts in it, including the carburetor body. Note: Do not use either carb cleaner on any plastic or rubber parts, itll eat them. What youre trying to accomplish is the removal of all varnish from inside the carb body, and jets. After theyve soaked for a couple of hours its time to spray out all of the small passages in the carb body, and the tiny holes in jets with the spray type carb cleaner and then follow it up with a blast of compressed air. Youre trying to make sure there is nothing clogging up those small holes, you leave one grain of sand behind and youll be doing this again so be diligent! By this point you should have a sparkling clean carburetor, all that is left to do is reassemble everything.

There isnt much to say here, just reassemble everything in the reverse order you took it apart. When the time comes to re-install the pilot screw make sure the o-ring, washer, and spring are in place and screw it in all of the way and back out two full turns. (further adjustment may be needed but this is a good starting point) When you re-install the slide components be careful not to pinch or tear the rubber diaphragm.

Float Adjustment:
While you have the carb apart and cleaned this is the perfect time to check the float height adjustment. Simply install the float and needle valve onto the carb body and hold it as shown in the diagram to the left. You want the needle to be lying on its seat but not pushed down. To check for proper adjustment measure from the float bowl mating surface, and the top of the float. (4) The adjustment should be 17mm. If you find its not 17mm then you correct it by ever so slightly bending the float bowl tang with a pair of needle nose pliers. (see arrow in this picture) Small adjustment result in big changes in the float height, so go easy. Once youve got it to 17mm youre all set.

Thats it! Now re-install the carb back in the bike and youre good to go!

Image Sources: - -
Note: The top image is of a CVK40. While it is a different carburetor than the CVK34 in the KLR 250 their layouts are almost identical.

This Kawasaki KLR 250 Carb Cleaning Information article was writen by :service Manual on date 7:45 AM
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