M8 - Knocking sound between 1800 and 2300 rpm ...
#21
08-11-2018, 10:46 AM
#22
08-11-2018, 01:38 PM
Road Captain
Yup, that's it ... not the normal ignition knock you would hear with fuel of low octane it is a deeper knock and as I say seems to be coming from the heads ... for me it is 18-2300, when hot and under 30%+ load, you especially hear it going uphill. It doesn't sound like something catastrophic is about to happen, just an annoyance really. I'm relieved to hear that others have the same sound, so if it is a problem then a lot of us have it.
#23
08-11-2018, 09:34 PM
This may be what I am hearing on my 18 RGU. It sounds like a tapping, rocker arm noise, most noticeable around 2000-21000rpm. It is very noticeable at that rpm. It sounds like a valve is out of adjustment or a bad lifter. If I park in the garage to try to locate it, I don't hear it, go figure.
#24
08-12-2018, 05:37 AM
Road Master
Would changing to a fuel with higher (or lower) octane rating make a difference? I believe the lower the octane the faster the fuel ignition but please correct me if I am wrong. I know HD recommends 91 octane and that is what I use, but in Canada we also have 94 octane in addition to 87 and 89 ... next tank I think I will give something diff a go just to see if there is a difference ... or, would the ECM just adjust for the different timing?
I dont think you’re hearing valve train noise, because to date I don’t think anything like that has been documented here. You’ve got a 2 year warranty anyway, so if in doubt about anything just enjoy the ride. If it gets worse have the dealer address it or at least have them document the concern. One thing I did was yanked the spark plug boots to insert some silicone/dielectric grease in them. Only reason was to make ‘em easier to remove on down the road. I also repositioned a couple of the wires because they were already showing rub spots. Any rub through can affect what the ECM is seeing, so inspect those also.
Max Headflow is a pretty savvy contributor here, so you may also consider what he recommended re: shimming the compensator. For now I’d tweak the fuel source and play around with the octane, and get more involved if nothing changes what you’re hearing.
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Ultra_RB (08-12-2018)
#25
08-12-2018, 08:47 AM
Seasoned HDF Member
While it could be the comp, if its more thock sound instead of a tick or pink, it could be simply be a sound coming from the intake/throttle body like others have said. It brings up the question as to what were all the engine mods including air cleaner and exhaust system. Generally from what I've seen the intake thock usually requires a intake / exhaust and cam change to happen. My stage 2 17RK doesn't do it but that is not to say someone else's won't.
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Ultra_RB (08-12-2018)
#26
08-12-2018, 04:22 PM
Road Master
#27
08-12-2018, 05:22 PM
Seasoned HDF Member
I've seen lifters rattle that in the RPM range but he says it don't sound like a lifter. A loose side small end of the rod or loose piston clearances can also make a noise in that range. My guess on the comp is a possibility but it could definitely be something else.
Heck it it don't change with temps, it might simply be something on the motor hitting the frame..
#28
11-21-2018, 05:29 PM
2nd Gear
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I think I know what knock you're talking about, OP, and it isn't ignition knock. Ignition knock is something else and sounds completely different. What OP hears, and what I also hear on my 2018 RGU, is a deeper knock more akin to wood blocks clacking together. It is most noticeable when under light throttle load while the motor is in the 2k to 3k rpm range. It isn't a pleasant noise, but it is a common motor noise. I've heard it before with other engines, including in-line fours, Goldwings, and Japanese V-twins.
How I experience this noise depends on whether or not I'm wearing earplugs (I almost always do wear earplugs), the traffic around me, my mood, distractions, and probably other ambient factors. Mostly, I don't notice it at all. I try not to. I do best when I keep my head in the ride and not pay attention to all the noises that big motor is making, while it works two feet away from my ears. I think earplugs make this noise more noticeable, because my foam earplugs tend to strip out clicky and windy noises but leave behind lower pitched clacky noises. Fairing type I think has a lot to do with how we hear the noises.
How I experience this noise depends on whether or not I'm wearing earplugs (I almost always do wear earplugs), the traffic around me, my mood, distractions, and probably other ambient factors. Mostly, I don't notice it at all. I try not to. I do best when I keep my head in the ride and not pay attention to all the noises that big motor is making, while it works two feet away from my ears. I think earplugs make this noise more noticeable, because my foam earplugs tend to strip out clicky and windy noises but leave behind lower pitched clacky noises. Fairing type I think has a lot to do with how we hear the noises.
Yup, that's it ... not the normal ignition knock you would hear with fuel of low octane it is a deeper knock and as I say seems to be coming from the heads ... for me it is 18-2300, when hot and under 30%+ load, you especially hear it going uphill. It doesn't sound like something catastrophic is about to happen, just an annoyance really. I'm relieved to hear that others have the same sound, so if it is a problem then a lot of us have it.
must be normal for all M8s.
im using 100 octane fuel. But does it on any octane feul.
silent when cold.
#29
11-21-2018, 07:32 PM
Road Warrior
Hopefully you got some answers to your issue. I have yet to experience any kind of abnormal engine noise below 1200 rpm. You still have warranty, let GAK figure it out. These M8 engines are so smooth compared to any previous V-twin I have ridden at any rpm.
Last edited by Warrant; 11-21-2018 at 07:35 PM.
#30
11-21-2018, 08:08 PM
2nd Gear
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others seem to have the same noise so its nothing to worry about. If i had loud pipes you would not hear it. It runs smooth at all rpm even when making the noise. Its silent under acceleration and when its cold.
I have 6 months warrantee left on the 2 year warrantee.