Traveling Tall is posting his performance upgrade build series with Zipper, and one of the guys working on the bike is said something rather interesting.
Time Stamp: 13:47

"Leaking Jets on the back side can be a huge part of why M8 engines can over sump with oil."
I was getting the impression that the sumping issue has more to deal with the case and oil pump design, and pressure build up?

Have you guys heard this before? In all the threads that I have read so far, I do not recall anyone mentioning Jet issues. (I dont have perfect memory so someone could have very well said something about it).
Thoughts?

Excuse the typo in the title, Spellcheck didn't check the title field.

 

Yes, have heard before. Jets mentioned many times. I’ve seen another video too about the jets being a problem & relating to sumping.

 

The jets or rather the gasket behind the jets was one of the first things HD identified as a problem early on. Later they started discussing oil pumps etc. etc.

 

Checking the jets is one of the things HD does when a sumping inspection is performed.

 

Ah, That might be why I havent seen much about it then, I only heard about the sumping issue after everyone else, since I wasnt planning on getting a harley M8 until after the softails came out.
I was still looking at the sportsters.
Thanks for the replies, guys.

 

The MoCo identified causes of sumping early on in their SB M-1450, from there its been a free for all. Heck, we could have our own game show called Name that Cause, take your pick, lots of opinions to choose from.

 

There are likely several causes of sumping.

 

I'll take Harley Sumping for $500 Alex

 

Yep, common problem early on and specifically called out in SB1450. But its not the cause for ALL M8s that sumped. I personally had 3 M8 engines that sumped and all 3 had their oil jets checked. All oil jets in the 3 engines that sumped were torqued to spec and secure from the factory.

 

T-Man did a video on the piston cooling jets. My bike has never sumped and my screws were a little bit loose. I think it's a good idea to change the gaskets as long as you've got the cylinders removed. I followed his recommendations using Cometic gaskets, allen head screws and sanding the jets flat. It's a really tight space trying to change these out when you have big hands like me. Using the allen head screws makes it easier to torque the screws than using the OEM Torx head screws. My jets were not flat but it didn't take much sanding on my granite counter top to get them that way. Take precautions so you don't drop your screws into the crankcase.