86 FLHT
Stock 8.5:1 comp., S&S E-Carb, Andrews EV-27,Samson Slip-ons, Twin Tec Ignition
Initial tuning: 1 1/2 turns out Rich
1 1/4 turns out Rich
Do I need to change my intermediate jet?
and.....how much does it cost to have it dyno'd and will they be able to determine what size is correct?
or....does anyboby out there have a similar set up that had to change intermediate jet?

 

runnwild1,

I have a 91 ultra with S&S E carb, SE-1 cam, SE ignition and coil, unknown turn-out mufflers (loud, I think theyoriginally came from Drag Specialties but cannot verify exact model) and have had it dyno'd (see my post "Dyno Report" in this section). I ended up with a #68main jet, but I don't know what the intermediate jet is. My adjustment on the idle air is just over 3/4 turn out from seated. This indicates that I need to try a leanerintermediate jet, although the dyno guy didn't say so. S&S claims that a correctly adjusted idle air screw will be between 1.25 and 1.75 turns out from lightly seated if the intermediate jet is sized correctly.The S&S website (www.sscycle.com)tuning guide statesthat if a correctly adjusted idle air screw is adjusted more than 1.75 turns out, it indicates that a richer intermediate jet should be tried, and below 1.25 trya leaner one.

If I am understanding you correctly, both 1.25 and 1.5 turns out on your idle air is rich. If that is true, it indicates that you should turn in your idle air screw more, which will lean the mixture. S&S says that you should incrementally, (around 1/8 to 1/4 turn at a time) adjust your screw in until the motor just starts to stumble, then turn the screw out in the same increments until the motor starts tostumble, then adjustthe screw to right in between the two extremes. Correct idle speed is900-1000 RPM's.The intermediate controls the mixture from approximately 2000- 3000 RPM's, and has some effect at idle, but the idle airadjustment, in my experience, has a dramatic effect from idle to 2000 RPM's. In my case, the bike has driveability problems if I am at all above or below the "sweet spot" adjustmentof just over 3/4 turn out. My idle air adjustment is very finicky, and once roughed in, I got my best final result from riding the bike (fully warm), then making a single very small single adjustment of about an 1/8 turn or even less, then riding the bike again. (Maintain the 900-1000 RPM idle) I could tell if I was getting the adjustment better or worse by simply taking off and accelerating normally in first gear, which is all that's necessary to put the engine through idle to 2000 RPM's.

I hope this helped, please keep us updated.

Scott

 

Be sure to shut off you acc pump when trying to get it jetted and adjusted correctly . It can mask other problems .

 

with your setup, start with a .28 or .295pilot, and 68 main. that should get you very close. turn the accl. pump almost off (just a little squirt) and watch your fuel mileage. if you are around 45 mpg the pilot jet is right, if mileage is low (35 or so) install a smaller pilot jet, if mileage is high (50 or so) go a size bigger.
now turn up the accl. pump (not a bunch, just to get a .25-.50 second squirt) that should smooth it out a bit.(you can play with that after you get the jetting right)Main jet will be set by hard accl. and high speeds, try up and down a few sizes and use the one that seems to give you a nice light tan color to the plug. Run a main jet for a few hundred miles before looking at the plugs. Most with yoursetup will run a 68 main. The goal is to get it to run nice and smooth when throttling, and still get good fuel mileage.
This is my method of jetting a mild to moderate tune road machine, it works very well, and is easy. Just remember, one thing at a time, and road test.

 

I put some new plugs in. think I had gas fouled the others. Ran it once with new plugs in garage. Kept the revs up between 1500-4000 rpm.
removed and checked. actually, they looked good. no sooty or black. Tomorrow I'm taking bike out, first time since surgery and upgrades.
1 1/4 turns out on carb. will ride awhile and check plugs when I get back in. if they don't look right or if performance isn't right i'll have to stop being lazy and do it the right way. thx, you've explained it to me very well.