Hello, I recently picked up a 2000 night train 1400cc. The bike is in great condition and seems to have gone through a good amount of customization (eagle screamer exhausts, open air cleaner, and a belt swapped primary drive). The bike however does not run well. Giving any more than half throttle causes a lot of hesitation and power loss. I suspected that the carb was dirty due to the bike sitting for a while. Today I opened up the carb and saw that it was clean. I then checked the jet sizes and noticed that the main jet size currently in the bike is 170. The pilot jet size is 45. I am curious what the stock jet sizes for this motor are. I looked at a parts diagram for my bike and looking at the part numbers, it seems that 190 is the stock main and 45 is the stock pilot. I don't know what to think of this however because that means that someone put an intake and exhaust on this bike then went DOWN multiple main jet sizes.... Does anyone know for sure what the stock jet sizes for this bike are? I also checked one of the plugs and the color was way whiter than I would like, indicating the bike has been running lean.

Thanks a lot for any help
Michael

 

Harley used the CV40 carb from 1989/90 until 2006... They were put on EVO 80" bikes, Sportsters, and Twin Cam 88" engines...

The stock CV40 carb, on my 2001 88" (1450cc) Twin Cam Springer, came with 45/190 jets.

On the off chance the person tuned it well, maybe with a richer needle and so he moved down on the main jet (big guess there....), make sure the carb is clean and all parts are in good working order.

I bought my 2001 Springer a couple years ago... Due to its age, and unknown service history, I rebuilt and cleaned the carb well. There was dirt, debris in the passages of the carb. I used an ultrasonic cleaner and then air pressure to clear it all out. I bought a rebuild kit which gave me the parts to change the slide, main diaphragm, accelerator pump diaphragm, float valve, and various o-rings and gaskets. I also had to reset the float bowl....

Once the carb is clean and with all good working parts, then tune it from scratch... That will tell you if you need a jet size change or needle adjustment/change..... If the mixture screw on your carb still has the EPA plug over it, then you will know it was never properly tuned...

For your reference, when I went to a high flow air cleaner and exhaust, I did not need to change the jets. I switched to a CV Performance needle and the mixture screw is about 2 turns. Mine starts and runs excellent...

Here is a good resource for the CV40 carb:

https://cv-performance.com/instructions-guides

 

Thanks for the response, I cleaned the carb today quite thoroughly and the bike still runs the same. I think what I am going to do is set the needle clip to the stock position and purchase a main jet kit. I'll start with 190/45 with the needle and mixture screw in their default positions and I will go from there by seeing how the bike rides and looking at the spark plugs.