New bike day. I traded in the Fatboy for a leftover 2025 Heritage, arrived yesterday. I'm a little concerned, I have a bit of oil coming out the back of the air cleaner, I put 102 miles on it so far. I'm hoping it's breaking in, and some blowby that will seal, but time will tell.

Looking good, I think. I had 45,500 miles on the 2021 FB, it was a great bike.

 

Take it back to the dealer. It’s not a “seal” issue. It’s probably over-filled with oil.

 

I second this. Same thing happened to my son with his 2025 Heritage. It was almost a quart overfilled. Oil pooled up in the A/C and smoking out the exhaust. Apparently checking the oil level is not part of new bike setup.

 

I'll third that recommendation to let the dealership see it, but I'd also just check the oil level myself.

 

Agree with the possible/probable oil overfill. It happened on my ‘25 Street Bob: it was overfilled at the factory. There is a service bulletin for it:

https://static.nhtsa.gov/odi/tsbs/20...18151-0001.pdf

You’d think dealers would check for it, but…. Nope.

 

My bike had an oil overfill situation. I was just told HD changed the oil level check procedure from on the side stand to vertical.
The 26 dip stick is also new, and they gave me one.
Odd how the “add a quart” is when no oils shows on the dip stick. At the correct level the dipstick has about 3/8th of an inch on the stick when cold. I recommend check it when hot.

 

There are vented options if it continues.

 

Thanks guys. The overfill from the factory was on the April builds, mine was built in July. I did check the oil, and after the first ride it was down to two dots above the add.

I called the dealer, he said its rare to happen, but the bike has the new crankcase vent system, and now is now known that condensate plugs the passage if the bike sits for a long time. Then when riding, it blows it out and lots of oil in the air housing. Its a left over 2025, so it says over a year. He said it doesn't really hurt anything, just makes a mess.

We will see. I cleaned it all out, brought the oil level up half way between add and full. I put 50 miles on, checked it, and it was dry. I have put 170 miles since then, and its still bone dry, and the oil level hasn't moved. So far so good. I will keep a close eye on it.

I love riding it, handles like a dream, sucks up the bumps.

 

I've heard that. My own 2025 arrived at the dealership 2 days before I rode it out, so no sitting for mine and no oil issues.

Although I believe Gen2 M8's have less blow-by than earlier models, and the breather is on the transmission cover rather than the cylinder heads, I still rerouted that breather line to an external breather so that it doesnt send hot oil mist, water vapor, or exhaust gases back into the intake. Keeps the pistons much cleaner over time...