Running rough at low rpm. Plugs? Water?

[Ungerbe]

Would a fouled plug throw an engine code on a 2016 RT? I think it’s bad gas because there are no trouble codes.

[Ungerbe]

It started running rough after winter so i think I have some water in the gas. Would a fouled plug throw an engine code. I don’t have any codes so I’m thinking gas problem.

[RICZ]

Did you put the proper amount of fuel stabilizer in the tank before putter it to sleep?

[Ungerbe]

No I forgot, but I did take it out a few times during winter. I have now got all the gas out and put some water treatment in and some Seafoam with a full tank of premium gas. It seems better but at idle it sounds like it’s running on two cylinders at times and over 2500rpm it runs fine.

[BLUEKNIGHT911]

No I forgot, but I did take it out a few times during winter. I have now got all the gas out and put some water treatment in and some Seafoam with a full tank of premium gas. It seems better but at idle it sounds like it’s running on two cylinders at times and over 2500rpm it runs fine.

I think the GAS is the issue .... There are products that deal only with WATER ( like "HEET " ) .... get one of those ....it won't hurt anything .... High test has nothing to do with the issue. good luck .... Mike

[BajaRon]

How many miles do you have on it? Coils can also go bad or have corrosion on the connections. Especially if no dielectric grease were used.

Most likely the fuel, as already assumed. Hope that takes care of it. You might want to run a tank or 2 of straight gas through it. That can also help.

[Ungerbe]

It’s a 2016 with 5982 miles. It ran fine the first day out then it happened the next day.

[RICZ]

when you go out next, grab some over 5K upshifts.

[Little Blue]

It started running rough after winter so i think I have some water in the gas. Would a fouled plug throw an engine code. I don’t have any codes so I’m thinking gas problem.

BAD GAS. ............Definitely Sounds Like The Case of Bad Gas. 1. Drain All the Gas from the Tank.
2. Put some 'Heet' water eater in your fuel tank. 3. Then Put in 3 or 4 gallons of fresh clean Fuel. 4. Start an Run the Engine for 3 to 5 minutes. 5. If it Sounds good take it for a gentle 10 minutes in the neighborhood. 6. Then if it is still running good ryde it for 30 minutes. Maybe have a chase vehicle.
7. Normally this will Fix a 'Bad Gas' issue. 8. Post up Your Results.

Good Luck on Your Mission. .........

[Ungerbe]

It has 5982 miles. I took all the gas out put fresh in with Heet for water. I usually stay abonve 3000 RPM with no lugging.
I have not seen any codes come up and have checked for codes. It still has stock plugs.

[BLUEKNIGHT911]

It has 5982 miles. I took all the gas out put fresh in with Heet for water. I usually stay abonve 3000 RPM with no lugging.
I have not seen any codes come up and have checked for codes. It still has stock plugs.

And how is it running ..... NOW .....Mike

[Ungerbe]

A little better but not much. I’ve only been 20 miles. I think I’ll drain it once more and put real gas with no ethanol in and just drive it and see.

[RICZ]

Try adding some Techron, it has worked for me.

[BLUEKNIGHT911]

A little better but not much. I’ve only been 20 miles. I think I’ll drain it once more and put real gas with no ethanol in and just drive it and see.

I think BajaRon may have a possible answer ..... however with less than 6000mi. COIL failure would be un-usual ..... More than a few members here have been cautioned about " Occasional winter use " ..... especially if the engine doesn't get up to FULL Temp ..... If you used the " HEET " in the gas that should have taken care of " water in the gas " issue. Honest and accurate use of B.U.D.'s might be needed ..... again good luck with this ..... Mike

[Joel The Biker]

If it had a misfire or coil failure, it would throw a code for misfire. My guess is a fuel issue and possibly a sticking injector, which will rarely throw a code. Try non-ethonal fuel, half a bottle of injector cleaner, and a couple ounces of marvel mystery oil in the gas. Run a full tank through it on a long ride with the engine at temp. Not saying I am right, just a guess, and what I would try on my own spyder.

[DriftersWay]

I had a similar problem. My cure was a spark plug.
Could also be the coil pack. Good luck

[Ungerbe]

Did it throw a code for the bad plug?

[DriftersWay]

No... At higher RPM's it would run fine.
BajaRon sell great plugs.

[Ungerbe]

I’m kinda leaning that way also. BajaRon has been helping me with this and I’m going to pull the plugs and have a look.

[Woodswoman]

A little better but not much. I’ve only been 20 miles. I think I’ll drain it once more and put real gas with no ethanol in and just drive it and see.

In December of 2020, I bought an F3-S. It was delivered to me with a half-full tank, and thanks to the weather I had no chance to run it at all. I put Sta-Bil in the tank, and the bike sat in my garage until Spring.

When I finally got to go out to play, I experienced just what you are experiencing.

It took two or three tanksful of non-ethanol fuel, each treated with Sea Foam, before the roughness and surging at low speeds fully worked their way out. No problems since.

Be patient and persistent about treating the fuel, and it'll get better.

[Ungerbe]

6FD9B0A5-8ED5-48AB-A90E-742B560231EA.jpgWell pulled plugs and they really don’t look too bad.

[BajaRon]

6FD9B0A5-8ED5-48AB-A90E-742B560231EA.jpgWell pulled plugs and they really don’t look too bad.

Yes, they do look good. It's probably what we thought in the beginning. Plugged injector, etc. If you had a bad coil. It would show up in a spark plug that was darker than the rest. Injector cleaner, straight gas and long rides are probably the cure.

[Ungerbe]

I think so too. I also checked the ohms on the coils and all read 1.5, so I think the coils are good.
I will clean the plugs and check the gaps, put it back together and put some injector cleaner in and run it for a while.

[larryd]

Just something else that just "MAYBE" worth a look...If the purge valve is stuck open...It will be a vacuum leak that could cause a low rpm miss...Purge valve malfunction do not set a code...

I had a purge valve problem with my 2014 RTS several years ago...It would stick open and cause hard starts when hot...when it would finally start it would act like the engine was flooded.. (and it was with gas fumes) Had to give it a a couple of good higher rpm's runs and all would be well...Till it decided to act up again and who knew when that would happen??? I ended up venting the gas tank directly to the atmosphere and blocking off the purge valve...Problem never reappeared...larryd

[spyder01]

Too bad you went thru the trouble of pulling the plugs, may as well change them now.


The fact that you don't have a missfire code pretty much rules out the plugs or coils or ignition system. What you're left with is a fuel problem. It's probably an injector issue, here's a way to diagnose.Take your air cleaner out and get a can of starting fluid. With the engine running at idle or whatever speed it seems to be the roughest, spray a small fine mist of ether into the filter chamber - you will be creating a work around for a poorly operating injector. Now you don't want to flood it out, so try to keep the spray small. If it sounds smoother, then you have proven the problem. If there's any way you can deliver the spray to just one cylinder at a time, you can figure out which cylinder is at fault. There's another way of doing it which is the way most pros would, and that is to use a small can of propane with a nozzle and spray the propane into the air filter chamber. I used to have one with a regulator and a deadman's valve in case you dropped it. Since you have the plugs out anyway, use a spark tester, crank the engine, and look for spark just in case. What I think has happened is that the tip of the injector is just a little clogged, which is something that can happen on bike that sits for a while. In a shop we would hook the injectors up to a flushing unit and push thru a mixture of 50/50 Techron and gas, or use a cleaner from Snap-On. You can't do that, so try running a heavy mix of techron or the cleaner of your choice thru that engine. It may take some time. Remember that at idle, the injector is only flowing a miniscule amount of fuel, so if it's even just a little sticky or clogged with dried fuel (varnish) then it won't have enuf to fire cleanly. Also, the guy posting above me has a good idea about the purge valve.