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Modify the sound of an M8

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Old Apr 26, 2026 | 01:41 AM
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Default Modify the sound of an M8

Hey guys!

I’m currently converting my Street Bob FXBB 107 into a chopper and trying to customize it as much as possible.

Now I’m looking to change the engine sound, if that’s possible.
What still bothers me is the high-pitched rattling sound coming from the engine area. I know this is typical for an M8, and I’ll never get it to sound like an Evo.
Still, I’d like to find out if there’s a way to modify it, so I thought I’d ask you guys!

The parts I’ve already swapped out and have all set up are the air filter, exhaust system, and camshaft (Feuling Reaper 465). For me, this setup is already set in stone and truly perfect!

The only thing that still bugs me is the rattling coming from the engine.
According to my mechanic, this is typical for an M8, but to be honest, I don’t even know what’s causing it.
Valve clearance? Timing chain? Ignition coil?

Maybe you guys have some ideas!

Thank you so much!

 
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Old May 2, 2026 | 03:33 AM
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Nobody an idea?
 
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Old May 2, 2026 | 04:41 AM
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Originally Posted by ninja_defuser
Nobody an idea?
https://www.hdforums.com/forum/gener...ear-plugs.html
 
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Old May 2, 2026 | 07:04 AM
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M8's sound like ****, the only good sounding ones I have herd had 1000'sss of dollars put into them, Cams heads and so on.
 
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Old May 2, 2026 | 07:47 AM
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Those modifications will definitely make it sound better. But It will never sound like an evo or twin cam.
 
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Old May 2, 2026 | 07:57 AM
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When you say chopper are you talking cut and rake hardtail lowered extended front end? Or are you going with performance bolt ons. Either way post a pic. Good luck with your project.
 
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Old May 2, 2026 | 08:11 AM
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Why would ignition coil make noise? If you we really doing a chopper get a cheap Evo.

 
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Old May 2, 2026 | 09:29 AM
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The parts I’ve already swapped out and have all set up are the air filter, exhaust system, and camshaft (Feuling Reaper 465). For me, this setup is already set in stone and truly perfect!
Did it rattle before you swapped out those parts?

Did you change out the lifters?

Did you use the original push rods or quick change ones?
 
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Old May 3, 2026 | 08:34 AM
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WELL
this started over seas. to get the american muscle car sound, european mfg's installed a sound system that put that sound through a set of speakers so that dinky 4 banger sounded like a 302 cobra.
actually cheaper than paying trump fuel tax.
 
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Old May 3, 2026 | 09:06 AM
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First of all, thanks to everyone for all the replies! I'm really happy that there are still forums with this much activity!

Originally Posted by touchdown
M8's sound like ****, the only good sounding ones I have herd had 1000'sss of dollars put into them, Cams heads and so on.
Yeah, I know they don't sound very good. That's why I'm looking for something that does it better.

Originally Posted by 02fx
Those modifications will definitely make it sound better. But It will never sound like an evo or twin cam.
​​​​​​​I know, but it would be better to just get started!

Originally Posted by 02fx
When you say chopper are you talking cut and rake hardtail lowered extended front end? Or are you going with performance bolt ons. Either way post a pic. Good luck with your project.
It’s a bobber with chopper accents. A clean, sweeping rear end, a sissy bar with a license plate, and forward-mounted footrests.
Not a show bike, but definitely not a performance bike either. A nice cruiser that’s supposed to sound great.

Originally Posted by Rounders
Why would ignition coil make noise? If you we really doing a chopper get a cheap Evo.
​​​​A cheap Evo isn't an option. I'm too attached to my bike for that. I just want to make it better.

Originally Posted by CoolBreeze3646
Did it rattle before you swapped out those parts?

Did you change out the lifters?

Did you use the original push rods or quick change ones?
​​​​​​​Yes, that rattling sound is typical of the M8, which is why I'm trying to figure out what's causing it. The pushrods have been replaced with Screamin' Eagle adjustable quick-install pushrods.

I messaged Feuling, and they recommended some lifters and washers.

They also suggested a different oil system, since it apparently helps with the noise as well.

But I’m not sure if that will actually fix the exact noise I’m hearing.
I really thought everyone was familiar with this humming sound.


​​​​​​​
 
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