Ok here goes,


I am in a thread on this subject on the shovelhead forum as well.


77 FLH with stock 74" motor, 2-1 fishtail no baffle running a cv carb from an 02 night train.


The carb had a dynojet kit in it until yesterday and the only complaint was a low end cough/stutter. It seemed to perform fine at high speed.


So I eliminated the dynojet stuff, replaced the slide and went to the n65 sportster needle. I did however leave the dynojet spring in, not sure why but I did. Now the bike runs amazing all thru the low/mid throttle coming up to speed. GREAT! But at high speed say when I would need to pass a car I crack the throttle open and there is little to no throttle response and very gradual speed increase.


currently its set to 190 main jet, 50 slow jet and 3 turns out on the idle mix screw. I tried the 180 main but the plugs turned white so I went back up.


I see no signs of air leaks, I check it quite often, the exhaust is not leaking, I have drilled a tiny hole in my right gas cap, next check is accelerator pump but I think its strange that would change in one day.


Potentially related note my clutch is getting up there in age and starting to wander forward at stop signs. I almost think there may be some slight slippage going on at these high speeds but still I am not seeing an increase in rpm's when I twist on it.


any thoughts?

 

Have you checked to see if the cable actually pulls the throttle ALL the way open?

 

What do you do if it don't? Can you adjust it out?

 

you replace the main jet till you get it to pull all the way - it could have been too lean or too rich - but he was using the shovelhead site and it was april of 2015 my guess he is still trying to find the answer - but tom did give him a direction and he never came back

 

LMAO, I'm talking about the cable not pulling it all the way.

 

while I agree that the cable is a possibility - but you have to be blatantly stupid to drive it with that much play in the cable and think its ok

so I will stand on the second option being a possibility with the jetting as I have seen that 50 times in the shop at least

 

Yeah, I get it. I'm just thinking, in my case, on one of my older bikes, I recently replaced both throttle cables. I was wondering the possibility that maybe , somehow (not a genius), that maybe one of the cables wasn't pulling the throttle completely open. I could of blatently neglected to check that. If this is the case, I would imagine that I should be able to adjust the cable to correct that.

 

you adjust the pull in cable - but un adjust the return cable first - then add return cable till you feel it influencing the pair then back it off till the assemble is free and snaps back smooth and quickly

 

Thanx!

 

One cable pulls WOT, one pulls it back just in case. (Hard to believe but years ago, they had one cable and no return spring)
Accelerated pump is what it needs when you WOT it quickly. Also down shifting helps.
You can WOT faster then motor can come on to power unless RPM is up there.

Not sure how you can live with a hole in cap. The fill cap is one way vent in. The vent tube has a one way out with a slight resistance so a slight pressure keeps liquid from surging thru.

​​​​​​That slight pressure fills fuel bowl if anything.