Spark knock

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Jul 29, 2023 | 03:08 PM

chargernut89

Thread Starter

Stage IV

Joined: May 2012

Posts: 4

Likes: 0

From: georgia

Spark knock

I have a 2021 road glide with a filter and slip ons, stock headpipe, using a dynojet pv4. The bike has always had a little spark knock but has gotten worse with filter and slip ons. I have had the tune adjusted twice by fuel moto but am still getting spark knock front and rear. Any ideas on what to look for maybe intake leak or something. I have tried a colder spark plug.

Jul 29, 2023 | 03:37 PM

60Gunner

Grand HDF Member

Joined: Sep 2017

Posts: 4,359

Likes: 1,219

From: Dubuque, IA

Get rid of the cat. Heat is not your friend. Don't lug it. Identify the !oad/rpm it's happening and retard the timing.a coup!e degrees at a time.
How do you know you have spark knock?

Jul 29, 2023 | 03:46 PM

chargernut89

Thread Starter

Stage IV

Joined: May 2012

Posts: 4

Likes: 0

From: georgia

I can hear it and it shows on the programmer.

Jul 29, 2023 | 03:50 PM

chargernut89

Thread Starter

Stage IV

Joined: May 2012

Posts: 4

Likes: 0

From: georgia

It does it pretty much anytime I moderately get on the throttle wether 2500 or 3500 rpm’s in 5th or 6th. If I have been riding for a while it will do it in any gear. Bike runs around 320* plus for engine temp

Jul 29, 2023 | 04:01 PM

gonemad

Seasoned HDF Member

Joined: Sep 2020

Posts: 8,158

Likes: 9,568

From: central NC

Quote:

Originally Posted by chargernut89

Here’s my TL/DR of similar behavior.

My 2020 107 did this before and after slip ons, new HD ac, and decat. FM wasn’t seeing knock events in my data logs. It was more of a pinging rattle, than a hard knock, like “castanets”

Some of it was resolved with the new tune, but my bike had other personality disorders that were “within spec” so I sold it at 17k miles. To the dealer I bought it from.

Last edited by gonemad; Jul 29, 2023 at 04:08 PM.