I bought a 2006 klx this past summer, the previous owner bought it from someone else and didn't know anything about it's mods. Once I got it home I realized it had a pumper carb, so that was cool, but I don't know anything else about it. My ignorance didn't really bother me until yesterday when I started having problems with it. First, the best I can tell from looking at photos on the internet it looks like a 33mm Mikuni carb, here are some pictures, maybe someone can verify that for me.





I've read about the 33mm pumper carbs that Bill Blue bores out to 34mm, but looking at photos, I got the idea this was not one of his (I could be wrong). I assume, but don't know, that the part he bores out is the part of the carb that goes in the boot on the engine side. I measured the inside diameter of this and the best I could measure was about 33.90 mm so perhaps someone has bored it out? Here is a photo of the part I measured.



The problem I developed is when I turn on the gas tank petcock, fuel starts running out of the drain at the bottom of the carb as well as the vent or overflow or what ever the hose is. I'm guessing the needle valve controlled by the float is compromised causing the gas to overrun in the carb but I'm puzzled by why it runs out the drain at the bottom of the bowl even though the drain screw is closed tight.
If you have any insight into my carb problem or any info about this carb please fill me in, I ready get beyond my ignorance about my bikes carburetor. If anyone knows where I might find instructions or a repair manual for this carb I would also like that. Lastly, as you can see, I managed to finagle the carburetor out of the bike but it wasn't pretty, any tips on future removal and installation would be appreciated. Thanks

 

If you don't know how to check float level, you are not going to be able to do any troubleshooting. If you do know how, then do it, make sure the float level is right. Then if you have gas draining out of the tube see if the needle or seat of the drain is damaged I'm thinking the bowl overflow goes out the drain through a passage in the carb. When I had a float stick in my 650 and had a high float setting in my old TM125 both ran out the drain line.

I would say with the measurement you got, the carb has been bored. I don't know what Bill does, but some do a taper bore much like automobiles use.

 

That doesn't look like my TM36-68. Probably a good chance you have a bored TM33.

In my sig line below is a link to FAQ page. Look in there for a variety of carb hints. Under my post #20, under the tm36-68 section, find a link to 'tuning manual' which may help.

 

Definitely a TM33 pumper. Though it looks old, the throat isn't quite as long as the one I've got. I'll take a picture and post it to this thread.

 

 

I took the bowl off the carburetor and reconnected the fuel line to the petcock. When I turned the petcock on gas flowed out the needle valve area, I manually pushed up on the float which in my mind should shut the valve but gas still kept flowing out. I haven't figured out how to remove the float to get to the needle or seat to see what it looks like. The metal pin that the float pivots on will not come out. As I recall the pin on the carburetor on my KLR 650 would easily slide out but this one will not budge, am I wrong to think it is supposed to slide out to remove the float, any ideas?

 

That looks like the carb that they used on a DR350.

 

First off, did the float needle actually move or is it seized in place. I had one seized up once, sanded the OD of the needle and the ID of the inlet to clean the light corrosion, using 1500 grit wet/dry.

You can carefully support one side pin support and tap out the pin using a slightly smaller pin or nail. Be careful, you do not want to break the body. I've encountered a lightly pressed in pin before, when I had to fix my own float needle.

If you don't feel absolutely secure doing this, don't do it. And do not apply the old axiom - if it don't move use a bigger hammer. This ain't a diesel truck! Carb bodies ain't cheap.

 

I just got the side pin out with a combination of some pb blaster and a harbor freight automatic center punch with the pointy end ground off a little. The outside of the needle had some crud on it that I sanded off with some 1500 grit. I'm thinking that was most likely the problem, we will see once I get it back together. For now it just feels like a victory to have removed the pin without breaking one of the support posts.

 

It's back together and running, (without leaking gas out the carburetor. Thanks for your suggestions and information.