I have a 2009 Nightster with Vance & Hines Shortshots and a Bulletpruf Spade Air Cleaner. The stealer installed the V&H last year when I purchased the bike. It ran great for the 5000 miles I put on it. I just installed the Bulletpruf Spade Air Cleaner last weekend and called the stealer to see what they would say about getting a FuelPak or similar system. The tech there said there really is no reason to tune the bike as the computer will adjust for what mods I have done. I rode the bike to work today and around a bit after just enjoying the sun but something just wasn't quite right. Every once in a while, the bike would just cut out. I guess choking is the best way to describe it. It wasn't a backfire but I could hear it through the air cleaner. It would do it once or sometimes twice and then be fine for a bit. I didn't notice anything I did that made it happen more than another. I brought the bike home and pulled the cleaner off. The butterfly on the throttle is definitely dirtier than when the cleaner went on 50 miles ago and I could really smell gas when the butterfly was open. I am wondering if the new cleaner is actually restricting air and causing me to run to rich. I also pulled the plugs and they were definitely on the black side. Any input is really appreciated. THANKS!! Eddie

 

I would definatley get some kind of fuel management system if you plan on using that ac.Get a pc3 or the new pc5.

 

Yeah, whoever you talked to at the dealer was a dumbass. The bike is running too lean because of the air cleaner, you need some kind of fuel management to adjust for the higher-flowing filter.

 

If the bike was running lean, the plugs would not be black. I did some research on the aftermarket cleaner and found out that the flow of this one is no better than the stock filter. Continuing the search on the bike, I found out that my crankcase breather was not functioning properly. After getting that all straightened out, the bike runs like it should. I am definitely going to keep an eye on those plugs just to make sure I don't start running lean.

 

mine does that every so often, just after starting it when it's cold and idling. after it warms up, no issue. hmmmmmm.......

 

Even though you got it figured out, it still wouldn't be a bad idea to look for some sort of tune in the future. It is FI, so the computer will do a little bit as far as compensation, however as far as fuel injection goes, the system is fairly primitive, so it won't go to far.

just a heads up

 

The computer isn't going to do much at all to adjust for exhaust or intake changes. The HD system uses narrow band 02 sensors which means they can only compensate about .5 on the AF ratio at the most. Read again...AT THE MOST. Your bike...but I would not take a chance on running the bike without knowing the AF is right. The bike is air cooled and the results could be devistating. The bikes are lean as hell coming out of the factory anyway. Thats why they run so hot. JMHO.

 

That's not actually how a narrowband O2 works. The narrowband can only report three conditions; Lean, 14.7:1 & Rich. Depending on the report, the computer is what makes the adjustments until the O2 is properly reporting. Your statement of a .5 compensation might be absolutely correct, but it's from the limitations of the ECU, not the O2. I do appreciate your input and will likely have the bike put on a dyno just for my own comfort to see where it's at. Thanks!

 

I don't want to get into a debate on techy jargon but let me add some details. The 02 sensors actually feed back a voltage to the ECM...not a lean, 14.7 or rich signal. The voltage drop is interpreted by the ECM only under preset conditions...ie. when the bike is running 14.6 or 14.7:1 AFR...I can't remember which right now. These are the only conditions in which the ECM actually reads the voltage and makes 'corrections'. There is a seperate table for this in the logic. The table either adds fuel or takes away fuel based upon the voltage drop. The MOST IT CAN ADD, under ideal conditions, is .5 to the AFR. I would interpret this as the best it can do, if its supposed to be 14.7, is 14.2. Now, this is when its supposed to be 14.7. But what if reality is 16:1??? This means the best it could do would be 15.5:1. Anyway, this is the way I understand the HD system to work. I have 2 bikes with the race tuners and have programmed both of them myself and read the manual. Neither bike has been on the dyno but I have added fuel to both bikes via modifying the HD stage 1 download. Both bikes run perfect, get around 40-42 mpg, and the plugs are perfect. I may be able to squeeze a little more out of them on the dyno but they are both running so good I hate to mess with them. Not to mention the 40-80 pulls and wear and tear. Anyway, that is what I know about the HD EFI...hope it helps. I am by no means an expert but have read a lot and talked to a lot of techs about it.

 

You are absolutely correct on the workings. I just kept mine very generic in logic. The only thing I do remember with the narrowband is that they can't report the actual rich or lean condition (via voltage), just that it is not the 14.7:1 that it should be. This is where the wideband is so much more useful.


I appreciate all your input and insight. Thanks!