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XR650L --Sudco Keihin pumper problem

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I just installed the sudco kit. I have rode it around the block about 3 times. It has 40 pilot, 158 main, ncvr needle in the middle clip air screw 3/4 out . Starts and idles fine. Runs great while accelerating. I can accelerate and slow down at slower speeds with no problem. The AP was squirting for about 6 seconds. I bent the tang out as far as i dared and got it down to about 3 seconds.

But when I run throught the gears briskly and then grab the brakes it backfires and dies. It won't restart unless i crack the throttle. Whats wrong?

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Sounds like momentary fuel starvation, from too low a float setting.

I checked the float level before I installed it. It is correct by all the info i can find, carb at a an angle and floats 8mm from the body. My KTM has a drain on the float bowl. I can pull the hose up the side, open the screw and use it like a water level to know exactly what the level is. I would switch float bowl but this one is a 3 bolt and KTM is a 4 bolt.

Years ago I had a mikuni drain plug with a hose barb that i used to check actual float level. I bought it somewhere. I wonder if anyone makes one if these. Probably not. AND since everything is going to FI, I'll probably buy a plug and make my own.

Does anyone know EXACTLY where the fuel level should be, not the float level, but the fuel level.

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I bent the tang to raise the fuel level. I didn't measure anything. I just took a guess. Runs perfect now.

Sometimes you get lucky.

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IF you connect a clear pipe on the float bowl drain and run it up along side the carb and open the drain screw the fuel should come up in the pipe and you can see where the float is set at. If memory serves me correctly the fuel level should be flush with the mating surface of the float bowl and the carb. When you set your float the important thing is to not compress the check valve spring tip. Just tilt the carb so that check valve close but doesn't compress the spring. Glad your bike is running fine now. However are you really getting a 3 second AP duration? It should be more like 1 second because if you pump your gas a couple times like we do in tight courses your gonna get a very rich and possibly bog like you have the choke on.

Your using the exact jetting as I am using. That NCVR needle is a great needle. Is that the jetting sudco now put into their kits?

Edited by D0T-C0M

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