2007 Road King. 40K miles. Bought it at an auction, seems pretty darn fast but no idea what is done other than I see a Big Sucker, and slip on's.
Put 93 in it, but at around 75-80mph in 6th, if I pour on the juice, I got some pings. None around town, and none if I accelerated modestly. Only when at highways speed in 6th and cracking the throttle open.
Any idea what I can do to fix this?

Edit: Oh was in the 50's today, bike seems to run nice and cool, don't think it was a heat problem. Also doesn't pop on decel or show signs of lean condition.

 

If you look at the 'RPM to gear ratio' on the above chart youll notice the RPMs will not be very different from 5th gear at 70-75 than 6th. But that difference will be enough to minimize or eliminate the ping. My suggestion is you do as I do and not use 6th gear unless your going to be cruising at 80+ for sustained intervals. This and retarding my timing has minimized carbon buildup which made pinging prevalent at the RPM ranges your describing.

 

AHHH, that's helpful. I don't have a tach and it is hard for me to estimate the engine speed. I am not afraid to run it down the highway at 3500 RPM, now I know that doesn't happen in 5th until close to 80mph.
Thanks a ton, I was afraid to push 5th gear past 70mph, because I had no idea how fast it was spinning.

 

A good tune should eliminate your pinging.

 

Mine did that when new, I put a tuner from fuel moto on it. Couldnt make it ping then. Have since changed cams, se255 new map still no ping

 

Riding in 6th gear at 75 mph is o.k. but gear down if you want to accelerate. I find the twin cam motors like a little higher rpm than my old shovel or evo. My 2011 road king runs nice at about 2800 to 3300 rpm. Seems happy there.

 

Mines does that when its hot or if i was in stop and go traffic

Aloha

 

when you whack open the throttle which allows more air, not only should fuel be added ( to match the extra air), but the timing should retard so that all that stuff burns at a time so that the piston is pushed forwards, not reversed

since the bike is new to you, a little detective work should be done to figure out if the EFI has been changed from stock.

if not, there are a few options so that you have good manners and streetability with 91 octane fuel.

as simple as nightrider.com xieds to piggyback tuners or downloads etc.
the first is a more fuel solution, the others may allow for timing adjustments as well as fuel.

In general, we want the timing as advanced as possible at all times...just below the point where pre ignition may occur. That gives the best power and the best economy and emissions.

pinging may be influenced by sharp edges in the combustion chamber or carbon deposits. the first can be a result of poor "modifications" or result from pinging and high combustion chamber heat burning or melting the aluminum.
the second is rare on EFI vehicles and may result from very rich mixtures ( poor tuning attempts) or oil burning in the combustion chamber.

my 2009 FLHTC pinged from new in stock trim under certain repeatable conditions: 2800~3200 rpms up a 6% grade at altitudes from 2500 to 6000 feet.
I used nightrider.com xieds ( about 8% more fuel) to solve this.
and later completed a stage 1 with continued good results.

I kept detailed notes of how the bike responded under various conditions...life is a test ride

Mike

 

Some input from my experience with my 07 RK. The pinging issue is fixable and can be fixed without a hassle.

Since it's a used bike, replace the spark plugs and make sure the gap is correct. I had pinging in my 2011 Limited. I removed the spark plugs and one had a crack in the ceramic. It fell apart in my hand! Standard plugs are just as good as the more expensive plugs.

If you do not have one you need a fuel management system. The big sucker and slip-ons give the engine more air so you need for fuel and you will get more HP. Without more fuel you run leaner, hotter and have pining due to the lean condition. Not good. You need a better tune if you have pining. A Vance and Hines Fuelpak will work for a simple stage one. It is easy to set up, a dyno tune is not necessary, and they have thousands of maps. You also can call tech support at Fuelpak ang they will assist with issues, if any. Many of my friends run them and they work fine. There are other fuel management systems and the Xids are also an option (inline module for the oxygen sensors to trick the engine electronics in thinking the engine is running much leaner so it gives more gas). I have no hands on experience with Xids but their is no adjustability. A HD tuner is more expensive but gives you the ultimate adjustability and does require a dyno tune. If there is a fuel management system you will have to retune it.

When your engine pings your knock sensors and engine electronics retards the timing which robs you of HP. The bike tries to complensate for the pinging. Once you get the fuel dialed in you will like the added performance. My 07 ran like a scalded dog once it was setup right.

I had an 07 Road King. If your bike does not have a IDS (Isolated Drive System) drive I "highly" recommend it. It is a new rear pully, from HD, that has rubber dampeners in it which quiets most engine vibs. and drivetrain noise down. It made a huge difference in noise levels and driveability for me. It significantly reduces the 5th gear whine. Your HD dealer can tell if you have one now. Some dealers will sell parts for 20% off. All the newer bikes have them.

I'd also change all fluids and run a heavier oil in the transmission. 20W50 is not thick enough and can create gear noise. HD says it's OK to run 20W50 and it is but 20W50 can make more trans. noise. A better fluid, like RedLine or BelRay will quiet it down and help to quiet the 5th gear whine in your first gen. 6 speed. Between the IDS and the trans. fluid your bike will run silky smooth.

Good Luck,
Dave

 

Downshift?