So, I've been having some issues with my 2011 FLHX.

Engine has been "hiccup'ing" at low rpm and low gears. This issue has occurred when I ride for a while, stop and turn off the bike (for about 2 minutes), and then start and go. Once I get up to speed, all is well. But at low RPM, the bike briefly (very briefly) loses acceleration and I hear the engine "miss" or "hiccup".

Well, thought I heard it today at low RPM in sixth gear. So, I took it into the dealership.

They couldn't repeat the issue nor could they find any problems. They did replace my spark plugs (had the plugs replaced at my 10K service and I'm about 14K miles now). They said the spark plugs were chalky white, and that meant my engine was running lean.

I added V&H slip-ons and a State 1 SE Heavy Breather last year (about 3 months ago) and did a one time flash download. Did not have issues between then and now.

So, any ideas on what's causing the low rpm "stutter"? And any issues with running the engine lean? The dealership recommended I buy the SE Racing Tuner...not sure if I'm willing to spend $500 if that's not the problem. But if it is the problem, I'm willing to.

Thanks for any help and info!

 

You defenitly don't want to be running to lean. Better get a tuner it will solve your lean problem

 

What he said. You will run cooler also.

 

If your going to do a tuner look into the power vision. Much better support and tons of info plus it doubles as a trouble code reader and clearer.

 

Hi, Skip. I'm curious, did you take it to Monterey County Harley Davidson in Salinas? There is a guy in the back, JD, who is a pretty amazing tech. If you haven't taken it to him, it couldn't hurt. But as others have already advised, you definitely do not want to run too lean. It is a bad thing. That said, we're not in as dangerous a region (I'm in Salinas) as many others if we are running lean by virtue of the fact that it's so cool here, but it's still not a good thing, and a tuner will most likely take care of you problem. There are other benefits that you'll notice as well, e.g. slight increase in torque, more responsive throttle, etc.
Once you decide on what tuner to go with, and either install it yourself or have it installed, you need to get it dyno'ed. That's where JD at Monterey County Harley comes in. He's VERY good, and a good tuner is just as important as having a good fuel management sytem on your bike with the mods that you have done to it.
I've used more than one tuner in our area for my dyno's, and if you'd like to chat about it for more info, feel free to PM me. I'll respond with my cell, and will be happy to share my experience with you.
Good luck, and I hope to run into you sometime at Baja Cantina, or River Inn! Gotta love our area for beautiful rides!!

 

All the tuners in the world are not going to help if you continue to run low rpms in 6th gear.

jus sayin

Bwana

 

yeah, define what you call "low rpms"

the motor wants to, needs to and makes power at rpms above 3200.

if you are putting around at 2200 rpms you are potentially damaging the lower end of the motor ( the expensive part)--- this is often called lugging-


( and at this speed oil pressure and volume are reduced- oil is part of the cooling system)


and this may be why other riders can't replicate this on your bike, they are in a higher rpm range- what experienced Harley riders consider "normal"



( yes we know the manual says you can go into 6th at some low speed--- under 65 mph on a flat level road and your motor won't be working to it's best.)

I am on my 6th Harley- 2 X 53, 63, 88, 95, 09- and ridden many others antique and modern.
I have a good sense of where these motors work well, and the modern motor NEEDS to operate at a higher rpm than my old panheads ( which have lower compression, manually retarded timing, hemi heads and are a different beast, although looking similar)


to you original question, an overly lean mixture will cause:

high temps- incl possible melting of the pistons/scoring of the cylinders/warping of the piston rings/damage to the heads and valves

increased tailpipe emissions: due to motor mis-firing

reduced power: due to misfire/incomplete burn / ignition timing retarded

pre-ignition, which itself may result in some of the above problems.


theoretical proper air fuel ratio ( AFR) is 14.7:1- ( and this will provide a steady rpm with a moderate load "work" placed on the motor) however a lower air ratio is needed to accelerate the motor and produce more needed power--- often that ratio will be more like 13:1.
EFI systems use sensors to determine how the motor is running and will richen the mixture when needed/ lean it out when it can like when the motor is just cruising at a steady rate/level ground.

sometimes the variables are outside of what the EFI control system ( ECM- Engine Control Module aka ECU) can compensate for, and that can include changes we make to the air flow into the motor and the exhaust out- or a sensor is malfunctioning OR the ECM is not reading and using the data properly.

there are some good articles on AFR on the net, and if you look at dyno sheets online, you will often see an AFR graph at the bottom



Mike

 

The only thing worse that running lean and/or lugging is
running lean and/or lugging with no oil.

Lugging = below 2500 rpm in higher gears. As prev stated, these guys (like to) run btwn 3000-3200

 

Thanks for the info all.

But, have a question about what people consider lugging. The owner's manual doesn't even talk about RPM's when referring to gear shifts...only talks speeds. Is there somewhere else where this is defined? I have to admit...I'm not convinced that I'm lugging the engine at 2200-2500 RPM. Not to mention the normal range of operation above 3000 rpm for all gears.

If operating below 2500 RPM in 6th gear is bad, why doesn't the manual talk about this?

Again, I'm trainable, but I want to see the numbers in a manual on this before I start operating my bike differently. I grew up on bikes with no RPM gauge, and lugging was defined by feel, power/throttle response, and sound of the engine. I do the same with my bagger, but now have an RPM gauge to make sure what I'm feeling is what the engine is doing.

The main point is that I've been riding this bike for almost a year and 15K miles...and my issues just started. The rider hasn't changed...something on the bike has. This is the first look at the spark plugs after new slip-on's, SE State 1 and new factory download. Those are the only things that have changed on the bike. Would these cause the engine to run lean? And if so, would lean engine cause the hiccup's? And if they do, why did it wait 5000 miles (3 months) to show up?

Again, thanks for the help on this!

 

Lean running is simply too much air to fuel. It could be as simple as some loose bolts on the pipes. Check the exhaust flange nuts, and sensors. If you can't do that, I will look at your bike with you. However, I agree with mkguitar as it sounds like a tuning problem to me. Also, I rarely use 6th gear here, unless I really want to speed.