KZ400 Single Carb - NEED HELP! (PWK35)

Which aftermarket petcock?
Which flatslide carb?

Will fuel continuously enter the carb float bowl if fuel is supplied by a container without a petcock? Perhaps this could be tested by opening the carb drain to determine whether fuel continuously flows out the drain. Which would indicate that there is a constant supply of fuel entering the carb when using the direct feed without a petcock.

Good Fortune!

I'm having a very similar problem with my 440 LTD. I Run the bike, it acts like it's starved of gas - can't get above 35 mph. Shut it off and restart it, and it takes off like it should; after about 30 seconds of riding, it goes back to being sluggish. It has only acted like this after I brought it in to get tuned up. I'm thinking they adjusted the float levels too low. I'm going to test the float level next and adjust if necessary - I'll let you know how it turns out.

Also, any other ideas as to why it would act like this, let me know.

Austin440 wrote: I'm having a very similar problem with my 440 LTD. I Run the bike, it acts like it's starved of gas - can't get above 35 mph. Shut it off and restart it, and it takes off like it should; after about 30 seconds of riding, it goes back to being sluggish. It has only acted like this after I brought it in to get tuned up. I'm thinking they adjusted the float levels too low. I'm going to test the float level next and adjust if necessary - I'll let you know how it turns out.

Also, any other ideas as to why it would act like this, let me know.

Was an Inline fuel filter fitted during the Tune up? Check it is not causing your restricted fuel issues.

There is no in-line fuel filter - I know this because I just replaced the fuel line (needed to be longer) because I put in a manual petcock. The manual petcock did not affect the fuel flow compared to the stock automatic/vacuum petcock; if anything, it made it better because the gaskets are new.

Treitz,

I took off the float bowls on my kz440 and found what I believe to be the solution to my problem, which seems very similar to yours. The float needle in one of the carbs did not follow the movement of the floats - it did not go up and down as I toggled the float up and down, it just stayed in the up position, thus blocking almost any fuel from filling up the float bowl. What I did to fix it was bend the tab that the needle sits on (or "tang" as the manual calls it) down about .5 mm to match the needle travel of the other carb.

Obviously I'll have to do some tune-up on it again with this change, but I am very confident that this was the source of the problem.