slight miss after cam install

[gobblerljw]

ok guys I am havin fits I have a 95 carb evo I just installed a ev27 cam and after I took it out it ran better more mid range but at about 1/4 throtle just idein in town it has a slight miss every now and then I went from 180 to 200 on the main jet plugs now look good I have one valve that is clickin and I need to adjust it but that shouldnt do this can anyone help me maybe I am just a worry wart cause I baby this thing since I got it oh yea and has 25000 miles thanks for you r help

 

[HDDon]

Has any head work been done to the motor? I would think that your problem is in the low speed circuit. What jet are you running on the low speed side? You can probably go back to the 180 on the high speed circuit.

 

[gobblerljw]

I am not aware of any head work but it did have adjustable push rods and that isnt factory from what I have read so I dont know of any and the cam was stock so I would be guessin I will readjust the valves and see what it does and by the plugs 190 was ok on rear cyl but lean on front so I went 200 and plugs look better

 

[glider]

200 Is rather large. You can't use the plugs to read mixture. The removal of the tetra ethyl lead ended that for us. What you see on the plugs is the color from the fuel additive that different companies use and not from mixture settings. You could be a bit rich.

You didn't mention what low jet you are using or if you shimmed the needle or not for better fuel flow but these things all come to play and the different circuits in the carb haver to be balanced out to work properly.

If you have for example a larger than normal low jet and your mid range is weak/lean as the needle starts to rise, you could get a miss from that. Low speed jet should be about a 46 with the high 185/190. Shim up the needle with 2 - #4 brass washers and go from there.
Many topics in self help about this.

Fuel and Carb Related Issues - Harley Davidson Community

 

[Breeze3at]

+1 on what Glider posted. At 1/4 throttle you are operating only on the slow jet and accelerator pump fuel.

 

[glider]

Maybe this will give you a better idea of the overlap of the different circuits in the carb and how they work...