Consensus question: Do M8’s burn oil?
Cruiser
Joined: Sep 2024
Posts: 184
Likes: 102
From: College Sation, Tx
it really depends on how/when you check it
Early on, I saw a vidga where a group was riding hard. On a stop one of them checked his oil and was surprised to see it really low. He added a whole quart, then took off hard, and not long after that his bike started smoking and puking oil out the filter and went into a bigger panic. Then they figured out that he severely overfilled it. You do need to be careful about stopping to check it right after or during a long hard ride.
Early on, I saw a vidga where a group was riding hard. On a stop one of them checked his oil and was surprised to see it really low. He added a whole quart, then took off hard, and not long after that his bike started smoking and puking oil out the filter and went into a bigger panic. Then they figured out that he severely overfilled it. You do need to be careful about stopping to check it right after or during a long hard ride.
Road Master
Joined: Feb 2019
Posts: 1,144
Likes: 951
From: Port Saint Lucie, FL
As others have alluded to it seems a common theme that those who find comfort in making sure their oil level is topped too the full mark are the same ones who will continue to use the most oil.
I'm beginning to think it's an act of genius on the part of the MOCO in that they've incorporated a failsafe system whereby they've ensured their engines always will be running a full oil level which is located at 1/2 stick as the prudent end user just keeps pouring it in with a concerned thought of "Man? I better keep and eye on that!" as they maintain the overflow working it's way through their breather tube system which in part is why I run a catch can so that crap ain't getting sucked through my T-body though I have noticed if I leave it at 1/2 stick? It stays there unless I do get to running hard and lose a small amount of rockerbox mist into the catch can.
Peace, Out.
I'm beginning to think it's an act of genius on the part of the MOCO in that they've incorporated a failsafe system whereby they've ensured their engines always will be running a full oil level which is located at 1/2 stick as the prudent end user just keeps pouring it in with a concerned thought of "Man? I better keep and eye on that!" as they maintain the overflow working it's way through their breather tube system which in part is why I run a catch can so that crap ain't getting sucked through my T-body though I have noticed if I leave it at 1/2 stick? It stays there unless I do get to running hard and lose a small amount of rockerbox mist into the catch can.
Peace, Out.
Road Master
Joined: Feb 2021
Posts: 1,084
Likes: 481
From: Phoenix Arizona
Well for one thing, the MoCo has a bulleting out (which I can no longer find, but will keep looking) that says 1Qt every 1500 miles is within spec.
Aha! Found it: https://www.tsbsearch.com/Harley-Davidson/TT461
Aha! Found it: https://www.tsbsearch.com/Harley-Davidson/TT461
As many other have responded.
i have a 2017 ( see sig line). I do my own oil changes. I do 5K for oil changes. I have a vented AC. And I do not see ANY oil use at all. When I check the oil level, it never seems to change.
If my bike , or anyone else's bike used a qt of oil in 1500 miles... time to rebuild.
IMHO
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,167
Likes: 11,263
From: San Diego, CA
Having a spec that allows for a quart of oil loss for every 1500 miles is akin to the MoCo bumping up the allowable TwinCam runout spec to 0.12", when most of the motorcycle world thinks 0.04" is excessive..
It's not the first time, or the last, that the MoCo has/will move the goal post (change a spec) to ensure lower warrantee pay outs...
Seasoned HDF Member
Joined: Jun 2014
Posts: 5,474
Likes: 6,345
From: pacific northwest
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Joe Kucinski
HDF Community Team
Joined: May 2022
Posts: 507
Likes: 241
From: CA
No oil consumption here.
The oil needs to be at riding temp to fully drain from the cooler and heads, and given enough time to do so - I check after riding it and give it about 5 min to drain back down.
The oil needs to be at riding temp to fully drain from the cooler and heads, and given enough time to do so - I check after riding it and give it about 5 min to drain back down.
Road Master
Joined: May 2008
Posts: 1,232
Likes: 428
From: Northern NY
I'm on my second M8. My first, 2021, 114, RGS used approx 1/2 qt in 5000 miles. Stage 2, vented at trans and also heads vented to atmosphere. I do all work on my bikes. Liqui Moly 10W-60 oil. It would show usage starting around 2500 up to 5000 on the dip stick. Bike ran great. My 2024 RG, 117 used some oil (HD 360) between the 1000 mi maint and recent change at 4500. Replaced with Liqui Moly 10W-60, 4 qts 10 oz with a dry filter. This puts the COLD check at 5 dots up from add on jiffy stand and HOT check 7 dots up from add on jiffy stand after idling upright for 1 to 2 min after a ride. I ran the same on the 2021. I check oil level frequently. The 2021 would drop the level a bit if I was running on the interstate on cruise at 80-83 mph for a 250 mile ride when checked at end of the day. Will see how the 2024 does. I have found it takes approx 4oz of oil to raise the level one set of dots.
My 2002 TC, FLHTC also uses approx 16-20 oz in 5000 miles. Same oil. I have had great luck with the Liqui Moly 10W-60 oil in my bikes.
My 2002 TC, FLHTC also uses approx 16-20 oz in 5000 miles. Same oil. I have had great luck with the Liqui Moly 10W-60 oil in my bikes.
Last edited by klammer76; May 3, 2025 at 10:20 AM.