carb

[fatone]

Ok the other day I noticed that there was some fuel dripping from my air breather on my 01 Fatboy. I pulled the breather off and fired it up. While idleing there seemed to be no problem. When I throttled it up it shot fuel into the carb but looked like a mist coming back out toward the breather. Someone told me to change the plugs so I did, but no change. Any ideas?

[frisco-rigid]

Hey Fat

That is generally caused by the Reversion Pulse , never heard of it huh..
Ok, maybe ya have..
Changing plugs does absolutely Nothing, I'm surprised he didn't tell you to check your tire pressure too..

Anyway, it's the energy wave (not exhaust) coming back through the pipes and getting past the open Intake valve and pushing the A/F mix right back outa the carb.. It's generally at certain RPM's and caused by lotsa things like cam design, exhaust system length and Diameter, use of a muff or not and removing the AC seems to amplify it..

Are you running stock exhaust.? Stock cam..??

Look up exhaust reversion and it'll become clearer than I can explain it..
Something else you might try is a set of AR cones,, they're often called Torque Cones..
I've used them in several big motors and got nothing outa them but my 93" shovel does get some benefit from them..
They just slip right in the head end of the header and hold tight against the exhaust gasket.. About 25 - 40 bucks depending on the catalog or shop..
The severity of reversion is generally a symptom of an IN-Correct combo of perf parts but possibly these cones will help a wee bit..

Faster horses (motorsickles)

[fatone]

Hey Frisco thanks for the info and no I haven't heard of it. I just bought this bike about 3 weeks ago and not for sure about the cam. It has v/h straight pipes. Is this something that I can fix on my own? This is my second harley that I have owned so I am fairly new at this and any more advice would be greatly appreciated. Do I just unbolt the exhaust and install from there? These AR cones, can they be picked up at any parts store or harley dealer only?

[tommyglide]

Those AR cones are made by Khrome Werks I think, and a Drag Specialties dealer can get them for you. Inexpensive to try, unbolt your header pipe right at the exhaust mani like the man said, you might want some new exhaust gaskets on hand just in case, and the AR cones slide right into the header pipe. I have them on both scooters, the correct (for me) exhaust pipes and I do not have your problem on either machine.

[frisco-rigid]

Hey Fat

Yes you can just as Tommy said, but to get the room to slip them in you will prob have to loosn all other pipe connections too..
And then, because the cones do add about 1/8" to the length of each header pipe the connections you loosened will tighten up slightly diff also..
You'll see, it's really very simple..

I wasn't able to find the KromeWerks cones in my catalogs but the ones I ran in the big motors came from JirehCycles.. Stainless steel, 15.00 bucks.. In Jireh catalog they are number 64-477..
The same ones in Dennis Kirk are $24.00 and the Samsom cones are,, ready for this,, $95.00 bucks..

Now let me add this---- it's prob amplified VERY much because of the straight pipes,, straights are Not good unless used on the drag strip..
It is very difficult to get correct carb tuning with straights especially in the RPM range that we all run in 95% of the time---- but, that's your call..
Hey,, don't take my word for it,, look up exhaust and straight pipes and you'll see..
Another band-aid/trickyou can use with your straights is the old "bolt & washer trick"..
If you want to see it,,I have some photos of it on this site..

Something else that works fairly well also is this.. I've done this with my 120" motor..
With muffs that have been emptied out you can slip them over the pipe far enough that the end of the pipe sticks in the wide body part of the muff 2 or more inches..
That also acts as a reversion wave block..



more money

[fatone]

All right tommy and frisco, thanks for the advice and I will give them try.