I own a 2017 Superlow 1200T that was placed in service in July 2017. I purchased it on August 3, 2018; at the time it had just over 2,200 miles on the bike. The bike is 100% stock on the engine--no upgrades or modifications to ECM, air cleaner or exhaust. I now have about 3,100 miles on the bike, and I noticed that it was running a little rough at idle and poor low RPM throttle control. It also runs hot.

i discussed the issues with the service manager at my dealer, and he told me that Evolution engines just run hot and are set very lean from the factory. I didn't totally buy this answer, so I removed the spark plugs and examined them. I observed some black residue (indicating a running lean condition) on the tip and base of the plugs that extends about five threads up the plugs. I took a soft wire brush and gently cleaned the tip and base of the plug and reinstalled them to torgue spec on the bike. It now idles and runs normally with reliable low RPM throttle control. This condition seems to be premature on a set of spark plugs with only 3,100 miles on them.

QUESTIONS: 1. Any advice or assessments from more experienced owners of Sportsters? 2. What should be my owners maintenance schedule for the spark plugs?

FYI. I installed a set of HD Gold spark plugs, and they caused the bike to run awful!!! I removed them and put the cleaned OEM spark plugs back on the bike and problems solved.

 

What makes you think its running hot.

 

The fuel cannot be very lean else it would burn out the exhaust valves or piston crowns but the engine is tuned as lean as it can be IMO.

I had an FP3 on my bike and observed the running temperature (that escapes me now). I applied the V&H map for a stock setup and the engine temperature dropped by around 10°C but I have forgotten at present what the running temperatures are as it was last year when I did this.

 

Black residue is the sign of a RICH condition, not LEAN.

John

 

Good answer and question. This is my first Harley, and the temperature from the heat shield against my right leg is hotter than I am used to. I bought the oil cap with the analog temperature gauge, and it was running over 260F when the ambient temperature was still in the 90s. I have read that this may be normal for an EVO engine during hot conditions. I changed the oil that was in the bike when I got it and replaced it with Mobil 1 20w50. I immediately got a 25+ degree drop in temperature. What I am learning is that nothing may be wrong with the temperature at which the bike operates; it is just different than what I was used to.

FYI, I misspoke in my original post, the black residue is a sign it is running rich.

 

Yes! Error in my original message. Thanks for pointing it out.

 

Any issues on cold start? Were both plugs blackened, or just one? Seems you used plural so I'll assume both. Over-fueling is the obvious issue, but why? It takes a fair amount of contamination to foul the plugs enough to induce performance issues. High fuel pressure, weak (cold) spark, baro sensor, or ECM issues come to mind. If it is in fact running rich while running, the cat will get hotter to burn the extra unburned fuel out of the exhaust stream.

Bottom line is that some diagnosis needs to be done on the fuel control system.

 

Wow, from everything I've read 260*+ is pretty high oil temps. Running Redline 20w50 I was seeing oil temps pushing 250* on 90* days running Interstate speeds and went with a Jaggs oil cooler. Oil temps now running in the same conditions might be 225*, worth what it cost IMO. The bike has Rush slipons, and a SE Stage 1 air cleaner, and has been reflashed with an FP3 Tuner.

I monitored the head temp once with the FP3, running at 70 mph for 20 miles or so on a mid 80* day I was seeing temps at 380*-385*. I was surprised how quickly they dropped to 340*-350* though when slowing down. Haven't checked it again since installing the oil cooler.

 

It is hard to know exactly what the black residue was. If you are bone stock, it is very unlikely you were running rich.

It is guaranteed that you are getting hot, oily, oxygen depleted air dumping into combustion chambers. How much varies bike to bike.

Also, 260* is too hot for the oil, and not normal for a sporty in 90* ambient temps.

Here is a Report LINK on how your engine performance and longevity is being compromised by the epa mandating HD dump crap into your intake.

A couple of photo's excerpted from above link-

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Here is some info on heat temps that your bike should be running at- Report LINK Go to the bottom to see the info relevant to Sportsters.

 

DK has some good info.
Odds are you are running lean and running hot.
OEM plugs are good, your don't need plugs that cost double.

If your bike is all stock, Id replace the plugs (verify gap), check the air cleaner and peek
into the throttle body intake. DK's catch can/ oil catching/ breather bolts are a great
product IMO. You could install that kit too and report back.

Synthetic oil, oil cooler and a air/ fuel computer tune IMO would reduce
any over heating issues.

Have fun.