Below is what I had posted on the Stage 1 kit manufacturers help forum and I am still having the same issues after trying their suggestions. Any input would be greatly appreciated

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Working on a 2006 Sportster 1200C.

The bike was towed in so I have no reference as to how it was really running before this install. Based on my friend it would barely stay running (which I did test) and it was bad enough to even try taking out on the road. I can say that whoever worked on it last removed the stock backing plate and had the air cleaner element just sitting up against the carb throat.

I installed both the Stage 1 and rebuild kit over the weekend. This went along with a K&N RK-3929 complete Air Filter kit. The bike was running a 180 main and 42 pilot jets. Based on the kit and its application I went with the 185 main and the 46 pilot. Everything else was as per the installation instructions. Entire carb was cleaned and rebuild kit installed along with the EZ-Just mixture screw and new packing kit. The slider has not been drilled.

Problems I'm now having: erratic dead spot / hesitation off idle under load (pulling off from a stop) both at cold & warm engine; I need to really ride the clutch to keep this from happening. Also will get a sporadic single pop through the carb while just cruising at around 35-40-50 mph; not giving any throttle at all, just a "cough", the bike bucks a little and then back to normal. Again, this is either cold or hot. I have adjusted the EZ-Just so many times and nothing makes a difference. Right now I have it set at 3 1/2 turns out. Frustrating part is one time I take the bike out all is well. The next test ride the problems are back.

After much searching of the forum I have run all the different tests I could find; checked for vacuum leaks, swapped out the accelerator pump, double checked the needle jet position, float level, etc.

I will say that ever since installing the kits the bike fires right up. At cold I set the choke, give the throttle one twist and it fires and runs good at idle; no hesitation or coughing when I do a quick snap of the throttle. Once warmed up I don't have to give it any fuel at all to start it, just hit the start switch and it fires and runs.

However, I don't feel comfortable giving the bike back when it is apparent problems still exist.

Any and all input would be greatly appreciated.

Thanks much,
Brian
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Also, as a follow up to what I posted on the their forum I have checked and double-checked the DTCs to make sure nothing has been stored - all is clear. Customer wants to pick up the bike tonight and I have already warned him about the situation. Guess I'll see what he thinks. Problem for me is if it's not 100% up to my standards then it's not good enough.

Brian

 

Dirty fuel or gunk in your tank? Mine will do an occasional cough, but it's nothing chronic.

John

 

I had similar issues with another bike (carburetor fed), and it was indeed stale fuel (bike was left sitting in garage with fuel - and lethanol - in the tank).
I was lucky enough that the condition wasn't so bad that I had to pull the carburetors and fuel filters, but a couple of Seafoam treatments via gas tank did it.

 

I'm not sure this has anything to do with your "cough" issue, but your jet combo for a simple stage-1 1200 is on the fat side IMO.

For a typical stage-1 06 1200, I'd use a #45 & #180 combo and about 2.5 turns out as a start point.
Many stage-1 1200's actually do fine with a 45 & 175 combo, but the main jet difference shouldn't have anything to do with your issue since it doesn't really come into play until 3/4 throttle.

Since your running a 46 pilot jet instead of a 45, I would expect your "turns out" to be less than the typical 2.5 turns out used as a starting point for a 45 pilot.

Note: this advice is based on a "typical" stage-1 1200 at 0 - 3000 feet elevation.

 

The jet combo I used was based on the recommendations as per the kit's manufacturer. Having put several runs on the bike along with quite a bit of idle time, I would pull & check the plugs which show no signs of richness whatsoever. Again, the AC kit I used was the K&N RK-3929 complete kit which, too me, seems like it will allow a significant amount of air flow - more than just using a "high flow" replacement element.

With regards to the idle air screw - I was thinking the same thing about how many turns I need to have it (more than I would've thought) especially with the #46 pilot jet. Granted, the bike will start to stumble turning in the screw when performing the typical adjustment procedures. However, if I were to leave the adjustment screw "as is" once the bike starts to smooth out (+1/8 turn) while backing out the adjustment screw, the bike will run even worse than it does with the adjustment being at 3 1/2 turns out.

Honestly, swapping out the #46 down to the #45 is something I have planned on doing just as a testing process of elimination. I mean what can it hurt??

Brian

 

I'm familiar with the K&N filter kit, it's similar to and probably flows almost as well as my NRHS Hurricane Flow and I'm running the 45-180 combo.

The one thing missing here is, what pipes are on the bike? If they're stock, your A/C isn't going to be flowing near it's potential and the jet size requirements would be lower.

3.5 turns out on the mixture screw, normally indicates the need to go up one size on the pilot jet, but I have a hard time believing that that's the case here on a simple stage-1 1200. Something else is going on here.

 

The pipes are not stock but for the life of me I cannot recall the manufacturer. Certainly not Vance & Hines or the like...."Bad xxxx" or something like that. (Not my bike)

And I fully agree with the thoughts in regards to the number of turns on the idle air in relation to the pilot jet. Thinking about picking up a CPS since I know they have been known to cause erroneous issues. May also dump a can or 2 of some seafoam into the tank since the owner can't tell me how old the gas is. Most likely I'll just say "screw it" and drain the tank and do a refill.

Brian

 

Hell yes, get some fresh 91+ octane in there and then run a tank full with Seafoam. 4-5 oz per tank should be plenty.

The CPS's do fail, I'm on my 5th, but every bad one I've had has thrown error codes. (P0373 or P0374).

 

fixed

 

Ok, so here's the rundown.....

Gas in the tank was very dark. It just looked old especially compared to the new gas. Drained the tank, removed the in-tank filter for inspection / cleaning, drained the carb and put 2 gallons of new gas in the bike. No change - problems still existed.

Back to the shop, removed the carb and put everything back to the way it was when the bike came in (180 main jet, 42 pilot jet, emulsion tube, needle, factory diaphragm spring, etc.) except I left the EZ-Just mixture screw in there because it certainly is convenient. Reinstalled the factory air cleaner even with the backing plate missing.

The bike ran great - no hesitation from a stop, no "coughing" through the air cleaner and I even tried to make it do it by riding the bike at 35 mph in 5th gear. So I have to wonder if the the K&N kit I was using just flows more air then expected and the #46 pilot isn't big enough to flow the required fuel in the low to mid-range scale.

At a loss as to what to do now. I know the customer wants his bike back but I can't say I'm looking forward to eating the cost of both the K&N kit plus the carb Stage 1 kit - not to mention all the time I have into this. Even as it stands I would still need to get a factory backing plate for the stock setup.

Any thoughts about getting a couple different larger sized pilot jets just to test my lack of fuel theory or am I more nuts than I'm letting myself believe??

Inputs - suggestions - ideas.....

Thanks to all,
Brian