Get it tuned properly!!!!

 

Tuned with Harley tuner and smart tune add on to maintain warranty

 

Absolutly get it to a good dyno person. You and the bike will both be happy.

 

Cant tune it with anything other than Harley or they will void my warranty. I added the screaming eagle tuner and then the Harley smart tune which also adds wide band O2 sensors for better tuning with the smart tune. Wasn't sure if this was a common problem or just mine.

 

try an octane booster if you feel knock is an issue, not sure what fuel grade you have near you, but make sure u use an unleaded fuel and if possible a recreation fuel with no ethanol, the advantage of none ethanol fuel is that it will richen up the air fuel ratio just slightly, if you have a basic harley download, you are probably lean anyways.

also run a good oil to help keep the oil temps down n motor cool, the cooler it runs the better the motor can fight off knock

 

I run premium 93 octane and tried octane boosters with no luck. The only places that have ethanol free fuel are about a 100 miles from me and they only offer 89 octane.

Tuned with Harley tuner and smart tune add on to maintain warranty

 

Preignition is Not Normal! The Dealer is a Dumb Azz! I'm guessing you have a Harley Tuner to preserve the Warranty. Get with the Service Manager and tell them to Fix It!

 

Thank you for all the responses, I was mainly trying to see if other people have experienced this issue or if it was just my bike. I was trying to work with the service department but they are going through a big turnover of management and the mechanic said he didn't her anything unusual.

 

Do you have another dealer in your area?

 

Not one that I trust unfortunately

 

does the dealer have a dyno, if not..track down a dealer that does and have them diagnose it on the dyno, you may have too much ignition advance, or a combination of that and a tad lean, its crude but tie off a plastic bag to cover about 3/4 of your air filter, this is a good way to richen it up and see what that does

 

Well I wouldn’t trust the one you’re working with now if they tuned and you have spark knock

 

From memory 13.8 AFR was the magic number. If the tuner could get that average across the chart the engine would run sweet. It won't produce the highest power numbers tho. Tuners like to see big numbers on the dyno sheet.

 

alot depends on the combustion chamber and parts..the range of 13 to 13.5 tend to give the best power

 

I have owned 2 M8's, a 2017 Street Glide and currently riding a 2018 Ultra Classic and have never experienced that noise. I put 25K miles on the SG and just had the 30K service on the UC. You need a HD certified mechanic to check it out as soon as possible.

 

I found this helpful video on youtube for 'reading' your spark plugs. They will be a good indication if your bike is experiencing detonation as well as your timing and excessive heat.

I have the 107 M8 with wood 22x cam, heavy breather, CFR slip-on and power vision tune with no knock under heavy throttle. It is a Freewheeler so it's pulling an extra 200-300 more pounds then yours.

Hope this helps,
Ron

 

Stage iv lots of compression you need some good octane boost not the walmart crap or auto zone some from the makers of race fuel . And a better tuner wider banded and a smart dyno operator with some patience

 

I never ran octane boost on my Stage 5 TC.

 

Shouldn't need to use octane boosters until you get over maybe 12.5:1 or 13:1 compression (assuming pump gas 91/93 is all you can get). But that's just a stupidly broad generality. Timing advance plays a part too in octane selection. You can tune an engine to run on 93 pump gas with a 12 or 13:1 CR by adjusting the timing, depending on other specifics about the engine.

Anyway, unless you got stupid ridiculous, octane booster shouldn't be necessary. Run 91/93 octane for high compression, have it properly tuned and have the timing properly set for running 91/93 octane. Unless you're going to the drag strip, there's no reason to tune it for a higher octane.

If you need octane boost on a street bike running 93 octane gas, you're not tuned right for street riding.

 

I did a stage one at 20,000 mi had it dyna tuned and after a couple thousand miles got a snap from right front corner of engine on hard acceleration. Just got back from dealer and he said he needs to retard the spark advance just a little. Was close to his closing so am to take back there and they would put on computer will take about 15 minutes to adjust.