M8 - Knocking sound between 1800 and 2300 rpm ...
#11
08-09-2018, 01:20 PM
Seasoned HDF Member
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.
#13
08-09-2018, 05:05 PM
Seasoned HDF Member
You could try adding a preload spacer to the compensator spring pack.. I would try to find a second small diaphragm spring and add it to the comp springs,Cup the small springs together, My 17 RK does not have the knock but my 07 egc with the latest comp has a slight knock, Adding the spring helped a bunch.
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Ultra_RB (08-09-2018)
#14
08-10-2018, 10:18 AM
Thanks to all that have posted ... and yes I will seek out another M8 bike to see if it sounds the same. I'm glad to hear that is seems "normal" and it's not doing damage to the engine. It is just an annoying kind of clacking noise and as mentioned just shows up under load in that 18-2300 range, all gears ... otherwise engine runs like a top ... funny tho and I forgot to mention this in my post is that it is most noticeable when the engine is hot ... I use AMSOIL 20/50 syn and AMSOIL in the other holes too ... but it did it with the Harley oil in it too.
One further question to the explanations of knock sensors/timing ... is what is actually making the noise? Is it actually something hitting something else or is the sound created by something to do with the ignition of the F/A mix???
Thanks again to all that have posted, appreciate the help.
One further question to the explanations of knock sensors/timing ... is what is actually making the noise? Is it actually something hitting something else or is the sound created by something to do with the ignition of the F/A mix???
Thanks again to all that have posted, appreciate the help.
#15
08-10-2018, 12:14 PM
Road Master
If we are talking about the same noise, and I think we are, I do think this is a totally normal engine sound. I've always been hyper-aware of engine sounds, and have spent a lot of time worrying about them, and wondering what causes them. In 2005 I owned two new Yamaha Road Stars. Very similar engine design, air cooled pushrod V-twins. These bikes had a "problem" in that, when hot, they would make this same knocking noise. It really aggravated a lot of owners. The internets were full of complainers. The knock had no functional effect. The engines were extremely reliable and good running. But when hot they could sound like they were about to throw a rod. The knock was very audible from idle up through around 2k rpm, then it disappeared amongst the general ruckus. I managed to convince Yamaha corporate to replace the engine on one of these two knockers. The new engine knocked even worse!
Also don't forget people hear things in varying ways, a lot of it having to do with hearing loss. Age related. One effect of this is to magnify certain sounds and/or attenuate sounds. Because the hearing loss doesn't usually happen in a straight line across the entire audible spectrum. One might be left with excellent perception of a knocking sound, but not be able to hear the wife from the pax.
Also don't forget people hear things in varying ways, a lot of it having to do with hearing loss. Age related. One effect of this is to magnify certain sounds and/or attenuate sounds. Because the hearing loss doesn't usually happen in a straight line across the entire audible spectrum. One might be left with excellent perception of a knocking sound, but not be able to hear the wife from the pax.
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Ultra_RB (08-10-2018)
#16
08-10-2018, 05:34 PM
Road Master
Knock occurs when a normal flame front (ignition) instead combusts spontaneously. The resulting explosion actually rocks the piston against the cylinder wall, creating that awful hammering noise. Engines can take a lot of abuse, but eventually the piper has to be paid.
Im sure You Tube has plenty of videos on this.
Im sure You Tube has plenty of videos on this.
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Ultra_RB (08-10-2018)
#17
08-11-2018, 06:31 AM
Banned
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Ultra_RB (08-11-2018)
#18
08-11-2018, 08:09 AM
Elite HDF Member
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It's not the sound of the intake valves closing coming back through the air filter box is it?
I know that the Rushmore bikes can have that sound at around that RPM range. My '15 Limited has had it from the get-go, as well as the Rushmore demo bike I rode.
Sounds just like a bottom-end knock, but it's not, and it's totally harmless and normal.
I know that the Rushmore bikes can have that sound at around that RPM range. My '15 Limited has had it from the get-go, as well as the Rushmore demo bike I rode.
Sounds just like a bottom-end knock, but it's not, and it's totally harmless and normal.
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Ultra_RB (08-11-2018)
#19
08-11-2018, 10:38 AM
Knock occurs when a normal flame front (ignition) instead combusts spontaneously. The resulting explosion actually rocks the piston against the cylinder wall, creating that awful hammering noise. Engines can take a lot of abuse, but eventually the piper has to be paid.
Im sure You Tube has plenty of videos on this.
Im sure You Tube has plenty of videos on this.
#20
08-11-2018, 10:44 AM
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.
