I'm trying to get someone who has more knowledge on the stock Keihin carburetor. I've had my bike for 4 months now, I rebuilt the carburetor and cleaned it completely but when I get on the throttle the diaphragm pump doesn't push more fuel in. It's just a single squirt then dies past a quarter throttle. I think it may be the spring not working but I dont really know what it would be like working properly. Thank you in advance.

 

Are you having issues?

Is the nozzle clogged? Do you have the pump diaphragm installed correctly? It only squirts a bit as you open throttle, not continuously while it's open. What jets do you have? How many turns out is your idle mix screw? Have you replaced the manifold seals, especially at the heads? All your vacuum lines are tight and in good shape?

John

 

Here is an exploded view of CV carb, make sure you didn't put diaphragm spring in wrong or diaphragm is torn. Also see where idle mixture screws is. Should be about 2 1/2 turns out. the idle mixture covers part of accel pump circuit

 

I have minimal knowledge of the Keihin CV Carb; however, the links below may assist you. One thing I have seen discussed is the needle jet getting put back in upside down that causes issues. There are pictures of the correct way it goes in the article about 1/2 way down. My 2003 XL1200S is working fine so I have not had to take it apart. Good luck.

http://sportsterpedia.com/doku.php/techtalk:evo:carb01

http://sportsterpedia.com

 

I feel pretty stupid but it was the main jet seat was upside down. I looked it up and someone said the short end goes in first but that was definitely wrong. It's all good now except I need a larger piolet jet.

 

No, it's a common mistake to reverse that needle jet, good for finding it!! I'm using a 45 pilot in my 883.

IIRC, I don't think that exploded view above shows the idle mix screw, since it's set and sealed at the Keihin factory for HD.

John

 

Good deal on finding the problem. Yeah from what I have read it is a common mistake, the picture in the previous link I provided gives a good view of how it should go in. All those little parts in there would give me a headache if I ever had to rebuild my carb. No reason to feel stupid, you came to the right place to get info so you could figure it out.