Milwaukee 8 Engine Problems
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Stage I
Joined: Aug 2023
Posts: 1
Likes: 0
From: Qld
Milwaukee 8 Engine Problems
Hi everyone, I am well aware that the early M8 engines from 2018 - 2020 had their fair share of mechanical issues. Am in right in thinking that the problems have been ironed out in the 2023 models? I currently have a 2015 twin cam and am think of upgrading to a new fatboy but I keep hearing things like stick with your twin cam
new M8s are nothing but trouble
Are they right? I am interested to hear from anyone that has one and whether theyve had a good or bad experience with it
Cruiser
Joined: Mar 2007
Posts: 163
Likes: 32
From: Amsterdam , The Netherlands
....depends how you look at it ,....the best thing what you can do , is changing the stock oil pump for an S&S oil pump + camplate ( and that counts even for the newest M8 )
That is the best solution in case you ride the bike constantly to his limits for very long periods of time .
In the beginning I was furious due to a stupid salesman ( at a lausy HD-dealer ) , who told me in 2019 that all "issues" were solved .( in fact the "oil transfer issue" and also wrong disc brake floaters )
But that stupid ******* was lying to me , or he was just incompetent for his job.
( no surpise that I've chosen to visit another ( and very fine ) HD-dealer from that time )
Well , ...later on , that "oil transfer issue" turned out to be a minor problem , what could be solved by removing a silly nylon oil reflector ring and also by mounting a tiny rubber vent in the inner primary cover.
Today , that tiny rubber vent is stock in all new M8 engines.
Another issue is , that carbon deposits can be build up on the pistons , on acount of the crank case ventilation . ( but that is something you can blame on the EPA restrictions / laws in your country )
Today I can tell you , this is my very best motorcycle of all I've ever had ,...but to be honest ,...it has a lot of ( S&S ) aftermarket parts in it now ,... some are necessary , and some are not )
That is the best solution in case you ride the bike constantly to his limits for very long periods of time .
In the beginning I was furious due to a stupid salesman ( at a lausy HD-dealer ) , who told me in 2019 that all "issues" were solved .( in fact the "oil transfer issue" and also wrong disc brake floaters )
But that stupid ******* was lying to me , or he was just incompetent for his job.
( no surpise that I've chosen to visit another ( and very fine ) HD-dealer from that time )
Well , ...later on , that "oil transfer issue" turned out to be a minor problem , what could be solved by removing a silly nylon oil reflector ring and also by mounting a tiny rubber vent in the inner primary cover.
Today , that tiny rubber vent is stock in all new M8 engines.
Another issue is , that carbon deposits can be build up on the pistons , on acount of the crank case ventilation . ( but that is something you can blame on the EPA restrictions / laws in your country )
Today I can tell you , this is my very best motorcycle of all I've ever had ,...but to be honest ,...it has a lot of ( S&S ) aftermarket parts in it now ,... some are necessary , and some are not )
Last edited by sjoko; Aug 22, 2023 at 05:16 AM.
Road Master
Joined: Jun 2013
Posts: 1,058
Likes: 953
From: Sarasota Florida
I have a 22 street bob and a 23 road king special. No problems with either one after 9000 combined miles, other than the untrustworthy, expensive local dealer. In my opinion, the M8 is the best motor harley has come out with to date, although it did have some early growing pains that should have been addressed before the bikes went on sale.
Of course, there are plenty of areas that could be improved like the seat, suspension, external breathing, exhaust sound, performance etc.
Of course, there are plenty of areas that could be improved like the seat, suspension, external breathing, exhaust sound, performance etc.
Road Warrior
Joined: Nov 2022
Posts: 1,538
Likes: 542
From: MN
Hi everyone, I am well aware that the early M8 engines from 2018 - 2020 had their fair share of mechanical issues. Am in right in thinking that the problems have been ironed out in the 2023 models? I currently have a 2015 twin cam and am think of upgrading to a new fatboy but I keep hearing things like stick with your twin cam
new M8s are nothing but trouble
Are they right? I am interested to hear from anyone that has one and whether theyve had a good or bad experience with it
Seasoned HDF Member
Joined: May 2012
Posts: 32,934
Likes: 36,031
From: Carlsbad, CA
There were no systemic issues with the early M8 motors. A few had sumping, fixed by the latest oil pump. A few had granny to primary transfer, fixed with primary vent.
Many put 1,000s of trouble free miles on their M8s including me.
Many put 1,000s of trouble free miles on their M8s including me.
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Seasoned HDF Member
Joined: Feb 2008
Posts: 22,999
Likes: 11,439
Yes a few issue cam up. Early was the transfer from Trans to primary fixed. The the sumpping two different causes one was in assembly the other was oil pump both fix. The M8 is leaps and bounds better than the TC. I have owned several of both.
TC 103 even back to the TC96 are good. M8 is better.
TC 103 even back to the TC96 are good. M8 is better.
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Cruiser
Joined: Mar 2007
Posts: 163
Likes: 32
From: Amsterdam , The Netherlands
History repeats itself over and over again ,....as soon as Harley-Davidson comes out with something new on the market , we have to deal with ( minor ) design flaws.
( .....and the aftermarket takes advantage of it )
Aren't we all used to that by now ?
( .....and the aftermarket takes advantage of it )
Aren't we all used to that by now ?
Last edited by sjoko; Aug 23, 2023 at 01:24 AM.
Seasoned HDF Member
Joined: May 2008
Posts: 21,130
Likes: 12,691
From: South Carolina
