Jet Needle
Grand HDF Member
Joined: Apr 2007
Posts: 3,723
Likes: 3,063
From: Brighton, MI
Yes it is. Don't know of the brand, but it's time to look at your main jet. Might be an aftermarket main jet/needle combo.
Stock CV carb? What bike is it for? Mods to the bike? Having problems with it running? Need more info...YD
Stock CV carb? What bike is it for? Mods to the bike? Having problems with it running? Need more info...YD
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Joined: Oct 2019
Posts: 52
Likes: 13
From: Petaluma
Stock carb. Vance and Hines exhaust. Wouldnt start. Replaced low speed jet #45 and cleaned the big jet (#195). I was going to upgrade and trick out the carb: shim needle, 7/16 drill to the vacuum port, brass fuel inlet, etc.
Runs great, not going to change the internals of the Keihin. Just swapping the plastic fuel inlet to a cv performance brass one.
Thanks for the response. Wasnt sure what kind of a needle I was looking at.
Grand HDF Member
Joined: Apr 2007
Posts: 3,723
Likes: 3,063
From: Brighton, MI
Not sure what you mean by "7/16 drill to the vacuum port". However, don't drill the vacuum piston/slide. Leave that alone.
The stock harley needles do not use a clip, and the tip of the needle is pointed. They have many different sizes and styles produced over the years by Harley. Learning the different CV needles is an education in itself.
Not sure of your knowledge base, but on yours, moving the clip down towards the tip will richen things up sooner. How is your mileage? How do your plugs look? See if your main has the "K" symbol indicating if it's a Keihin jet. Maybe someone here will recognize what brand needle you have. I know when I bought my bike used, it had a dynojet needle, dynojet emulsion tube, and dynojet main. Gas mileage was bad, and plugs fluffy black. I am now running a stock 195 main, slow/idle at 48, and a Harley Nokk M needle, That is with a cam, free flowing air cleaner and mufflers.
Just another note about needle that is often over looked: different lengths change when the midrange fuel circuit starts to come in. Shorter the needle, the sooner the midrange starts to come in and ultimately the sooner when the main comes into effect. The different thickness (width diameter) of needle changes the amount as well. A fatter needle reduces the amount of fuel coming in to that circuit. A thinner (smaller diameter) needle increases the amount of fuel coming in to that mid range circuit also. Just a little side note information...
Make sure you take note of the angle of the old fitting (before you remove) so you can duplicate with the replacement brass fitting. This is so your fuel line from the tank flow smoothly with no tight bends and at the correct angle. I almost got this wrong when I did mine years ago.
Glad to hear the bike is running good again, if the slow jet was clogged, then make sure your transfer ports are clear as well. YD
The stock harley needles do not use a clip, and the tip of the needle is pointed. They have many different sizes and styles produced over the years by Harley. Learning the different CV needles is an education in itself.
Not sure of your knowledge base, but on yours, moving the clip down towards the tip will richen things up sooner. How is your mileage? How do your plugs look? See if your main has the "K" symbol indicating if it's a Keihin jet. Maybe someone here will recognize what brand needle you have. I know when I bought my bike used, it had a dynojet needle, dynojet emulsion tube, and dynojet main. Gas mileage was bad, and plugs fluffy black. I am now running a stock 195 main, slow/idle at 48, and a Harley Nokk M needle, That is with a cam, free flowing air cleaner and mufflers.
Just another note about needle that is often over looked: different lengths change when the midrange fuel circuit starts to come in. Shorter the needle, the sooner the midrange starts to come in and ultimately the sooner when the main comes into effect. The different thickness (width diameter) of needle changes the amount as well. A fatter needle reduces the amount of fuel coming in to that circuit. A thinner (smaller diameter) needle increases the amount of fuel coming in to that mid range circuit also. Just a little side note information...
Make sure you take note of the angle of the old fitting (before you remove) so you can duplicate with the replacement brass fitting. This is so your fuel line from the tank flow smoothly with no tight bends and at the correct angle. I almost got this wrong when I did mine years ago.
Glad to hear the bike is running good again, if the slow jet was clogged, then make sure your transfer ports are clear as well. YD
Seasoned HDF Member
Joined: Aug 2008
Posts: 5,052
Likes: 993
once you drill, cannot go back. this can have serious issues, oscillation being one. the signal actually travels faster with the smaller size. in automation, we use small sense lines and larger control lines. the 45/190 is right and borderline to the rich. i run the 45/200.
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Joined: Oct 2019
Posts: 52
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From: Petaluma
Thanks guys. The Keihin is back together. Thoroughly cleaned. A few new gaskets. I had plans on "improving" the carb, but I'm leaving it alone. Except for the new brass fuel fitting, which is on order.
Great information above. I had never really looked at the needle before to realize it wasn't stock. Learn something new everyday.
Great information above. I had never really looked at the needle before to realize it wasn't stock. Learn something new everyday.
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