Got a 78 FXE few months ago
It's my 5th shovel, but the first one to have an S&S Super E carb and the first 74"

The engine looks pretty much stock, has points and timing looks right (strobe light test)


fires right up, idle is fine, high rpm riding is just fine.
It has draf straight pipes

Problem: I did not feel it rode any better or harder than an 80" with the stock Keihin.
Cruises fine at low rpm (+-1200) but above that it sputters, backfires a little and coughes, any gear. If I give throttle it cruises at higher rpm just fine and steady, no problems. Off idle is fine with a little thottle, but coughs with a little more, unless I give throttle few times and bring rpm up.

What I did: put 4" baffles trying to get some back pressure. no noticerable difference
Reset all the carb settings and tuned it: idle, mid, high and acc. pump: runs a little better... but still ho huge difference compared to a Keihin and still the same issue at cruising speed.

Took off the bowl yesterday, it all looks clean, no deposits or anything.
Main jet is a 70 and mid is a 28

Carb manual says a stock engine should have a 66 and 28


Ideas or considerations?

**edit**

checked the plugs the other day... they pretty black.. they are brown on all my other bikes.
cleaned them, brushed them and put them back... no difference.
I also adjusted the clautch to make sure it engages and doesn't slip... no help

 

depends on altitude -- where are you? a stock 74" with open pipes at sea level uses a main jet 68 and a idle tube 31/32 -- over 5000' you drop the jet size -- mufflers same smaller jet -- cam changes do not affect the jetting -- im at sea level with a 80" open pipes and i use a 70 main and a 32 idle -- they also make a wider air cleaner for the S&S it gives 35% more air flow -- works really well -- also go to O'Reilly auto parts and buy a set of AUTOLITE XS 65 best plugs i have ever used ..

good cams for a stock 74 -- andrews "A" -- sifton 112,116 101 - none require head work the 101 can be run with solids but works best with hyd -- the 112 either -- the 116 solids only but they dont make noise -- the "A" either..

you can make solids out of your hyd -- turn the hyd unit over and punch out the lil tit -- remove the guts drop in a nut -- adjust solid --

 

also once the plugs are gas fouled you have a higher chance of the plug being no good.. it will run but brake down under a load buy new ones --

 

I live in Charlotte, NC... I think around 600ft above sea level
I just want to get the bike running ok now... will start rebuilding the whole thing ground up this winter, so now I am riding it to find major issues.
It will probably become an 80" with a different carb and for sure different pipes (no drag pipes)... let's see later on this year

I think I can try a bigger idle jet to start with...

 

.0295 idle and 68 main , turn the mixture screw all the way in and back it out 1 1/2 turns . That's your starting point . Get her warmed up and the mixture screw you turn in till it starts to pick up a bit and stumble then turn it out till it does the same and you set about half way between the 2 spots with just a hair to the fat side and your there . If the mixture has to be turned out more than 2 turns to run then you go to a bigger intermediate jet .031 . If the carb run better at 1 turn or under drop down to .028 jet . S&S E is about the most simple carb to tune there is .

One thing to check and get right is the accel pump adjustment and you need to refer to the booklet for doing that which you can get on S&S's web site for free .


The carb isn't gonna magically add any horsepower or pull to the bike don't care what you bolt one to most put one on because they like the looks of the S&S or they got tired of playing with the stock carb thinking it too wasn't giving enough power . Shovels are a heavy flywheel bike , they don't spool up fast like evo's or a sporty will so everybody thinks they are under powered . They are the last of the old tractors made to pull a lotta weight at steady haul all day long , never where a hole shot high MPH bike unless they had been reworked with lighter wheels or stroked , then they can complete with the later bikes .

Most the evo guys I knew quit riding with me after I stroked out my old shovel to 88" , not only could she *** rape 90% of them off the line I could outrun them uphill loaded 2 up with gear in the mountains around here on all the runs

 

^^^^^ what twisted said

 

I didn't expect any magic... just wondered how would a 74" with an S&S would run... the shovel I've had were all 80" with Keihins

Anyway... put a .0295 and 68 in te bike. A very quick road test confirms the problem is solved. Will still do a liiiiiiiiiiiiiiiiiiittle fine tuning and let's see. No more hesitation at cruising speed.Top power not awesome... it just runs fine.

thanks guys!

 

You can try a 70 main to see if you pick up a little top end , it's the easy one to change just drop the bowl drain plug .

 

will use the 68 for a while and then try the 70 back and see
thanks!

 

this is one of my plugs (new)after about 60 miles Interstate riding and some more aorund town miles.




It actually looks a little more on the brown side live compared to the picture
Bike rides fine, got rid of the problem
Cruising 65 in the Interstate just fine