'75 FX with 80" kit, 3 5/8" bore. I have an older Super E installed (without a main jet air bleed, just the hole), and an aftermarket air cleaner. I've been through the carb guide repeatedly, and have got it very close after bumping the intermediate jet to .031 (it was hiccuping on throttle at low speed constantly.

Now it is only hiccuping when I am coasting or changing gear. As I roll on throttle and release clutch it wants to cough, sometimes hard enough to kill the motor.

I can't imagine the current jet sizing being to small at this point. Could this be a problem with the accelerator pump assembly? It is all pretty new (rebuild kit put on by shop last summer.)

I've followed the letter of the carb guide, and have gotten it almost there, even removing the bowl vent plug due to the different air cleaner. Thanks for any advice.

 

shut the accelerator pump off for tuning. then bring it back in for acceleration, after tuning.
Some people run with it off completely, even after tuning.

 

What cam, compression and ignition are you running in that modified 74"er?

 

Count me as One!!! Even my Ka-sneeze carb is only set to a Partial squirt
My Concern revolves around
"and an aftermarket air cleaner"
Difficult to improve on the S&S air cleaner...and If you are Not using a K&N filter in any air cleaner.. Good luck...I can't help.

 

I have an Andrews H grind cam and running points. Not sure of compression but no greater than 9:1 I’d bet. Probably less.

As for the air cleaner it is one of those V-twin sandwich style with th perforated sides. Foam filter. Thanks

 

Sorry should've asked how long have you owned the bike and what changes you made.. For the air bleed you mean that there is no jet in there? And that the casting of the carb body is wide open?

 

Get an air cleaner or suffer from not being able to Tune properly.

The Early S&S had just a hole... on those we drill and tap for the replaceable air bleed "Jet"..Unless it simply comes into it, and you do Not intend a ThunderJet...which is where the Replaceable air bleed "jet" came from in the first place

 

go after the intake first a 31 is a big jet for that size motor and using a stock cam - that could be part of the problem but intake air leak is on the page to do - it has o rings they are always suspect in tuning out issues

 

I always point to intake leaks now.
I learned the hard way, and "fixed" everything imaginable until I discovered the leak and sealed it.
My bike ran like crap, and fouled plugs like crazy, until I cured the intake leak.

 

Ditto on intake leaks. Carb braces are mandatory and the stouter the better. I and many others use "aircraft" style manifold clamps.

Those sandwich style air filters with the perforated wraparound are quite restrictive. I'd install the correct S&S air cleaner assembly ASAP.