I ride a 2015 Sporty 48 thats currently sitting at around 7k miles. It has no motor work done to it, only performance affecting mods so far are an Arlen Ness Big Sucker stage 1 intake and some Vertical Twin pipes from Kinetic Motorcycles which I plan on changing(dont waste your money with this company). So anyway after I start my bike up for the first time for the day and let it run for a few minutes, if I try to rev it up a little it damn near kills its self completely. I have to go thru this almost dying thing two or three times and then it will finally rev up like it should and runs fine for the rest of day. BUT there has been times where id ride for a while and then come back to it say 4 hours later and i have to go thru the whole thing again. Im still new to harleys so im not super knowledgable about it all yet but it sounds like its just choking its self to death if that makes sense. I ran some fuel injector cleaner thru it about a month ago as well. So whats the deal here???

 

Am I reading you right: you changed both intake and exhaust but you don't have a tuner? Or at least some kind of fuel enricher? If yes, then that's your problem I think.

 

You are correct, it has not been tuned yet. I just didnt think not being tuned would make the bike almost kill itself from simply trying to rev it up

 

You're right, it shouldn't do that. Let's wait for the experts to weigh in.

 

I'm going to say that it's too lean to run when the engine is "cold". I have a bone stock 2014 1200C and it will stall if I try to ridie it too soon after a cold start. I'd check for vacuum leaks around the intake. If you don't find anything you can let it run a bit longer after the cold start but the best fix would be a tuner.

 

The Engine runs Lean from the Factory. With the changes, Intake/Exhaust you've made it Too Lean. Put the Stock air cleaner back on and see if it improves.

 

HD has actually made the Sportsters run richer from the factory starting in 2014 with the can bus ECU software, lambda based AFR and heated O2 sensors, at least compared to the 2007-2013 models.

Normally if you change just the air cleaner or the pipes you can get by without a tune, change both and you should adjust the tune.
(my opinion is the pipes usually change the air flow more than just an air cleaner so I would tune if the exhaust only is changed except for just slip on mufflers)

With the cooler weather, the ECU will add more "cranking" fuel and run richer when first started.
The difference in injector time while cranking is about 50% more injector open at 61 degrees compared to about 86 degrees
There are two fuel tables that are temperature related, cranking fuel and warm-up fuel.
The warm up fuel additions decay out based on run time, letting the bike warm up for a "few minutes" that additional fuel will have decayed out.
It usually takes about 60-90 seconds of run time for it to decay out (it adjust leaner every few seconds until it reaches a value of 0 added fuel, the colder the engine at startup
the added fuel is greater along with the decay time length.
The 2014+ Sportsters go into "closed loop" sooner, thanks to the heated O2 sensors, the closed loop engine temp starts at about 86 F compared to the 149 F for the 2007-2013 models.

Looking at the pipes, they may be the source of the problem, I think they would definitely need a change to the tune even if you just changed from stock to them.
Much like short "drag pipes".

Did you have to use a O2 18mm to 12mm adapters to install your O2 sensors?
If you did make sure you do not have an exhaust leak around the O2 sensors or adapters.
Also confirm your pipes are tight and have no leaks at the heads. (would leak more just after start up until the pipes/heads warm up and reduce the leak)
Exhaust leaks will affect the O2 sensor voltages, usually resulting the ECU adding more fuel.

You didn't by any chance switch the Front / Rear O2 sensor connections when installing the pipes?

How do your plugs look? Check them after your "few minutes" of warm up.


I would be looking for a Power Vision tuner from Fuel Moto or DK Custom to adjust your tune.