I think we have determined that the build date has nothing to do with the problem.

My build date is 9/16 and doesn't have the issue

 

Thanks.....I found it. Mines 4/17. I'm keeping tabs on it.

 

To recap so far.. From what I can tell. HD found an issue where during assembly the mainshaft seal could be damaged. They replaced the mainshaft spacer with one that had more taper, presumably to keep the assembler from damaging the seal, possibly folding it over.

If this is the fix, then those who have not seen the issue probably won't have a problem. You can quit here is you want.

Side note is that there seems to be some that have had the issue occur later but may not have been running the bike hard to start. Also some appear to have had the fix and still have the problem. Still It's possible that the new seal may not have been installed properly.

IMO The fix is plausible. It wouldn't surprise me if HD has a history stemming back to twincams that have had a hydraulic clutch to have had this issue and it was fixed so they came up with the M8 fix.

It's in my opinion that the main reason for the oil working it's way down the mainshaft pushrod hole has to do with the fact that the hydraulic slave cover and trap door clearance is too little coupled with the fact that first gear is on the end of the mainshaft with is the smallest gear in the set. It coupled with possibly the anti rattle gear are forcing the oil into the trapdoor mainshaft bearing. The oil flows trough the bearing and fact that the clearance for oil exiting the other side is small allows for the possibility of the oil to rise and flood the pushrod area allowing the oil transmission oil to flow through the pushrod tube.

If makes sense that if there is anything generating a vacuum in the primary that would definitely speed up the process. IMO HD did find a good fix with discovering the seal damage on some bikes. I suspect that other factors are involved to exacerbate the situation as some have seen the problem start after some mile but there is no discussion as to whether riding habits changed.

IMO if you don't have the problem with your ridding style don't worry about it.. I've got an 17 RK built in 11/16 that has really only showed the issue twice and that was extend riding at 75-80, over 50 to 100 miles.. For me it seems to be getting better. Based on my thought of what is going on there are a number of ways to fix the issue. HD seems to want to try the compensator sprocket shaft issue first. I think that sealing one side of the transmission mainshaft the slightest, or adding clearance between the trap door tranny cover around the bearing would be a good cure.. I still suspect that in some cases the slip assist clutch and possibly the tranny vent are contributors in the issue.. Some of that theory might be tainted by my hating the slip assist clutch tho.

 

Great summary, thanks for the post.

I've got about 4500 on mine, 3400 of it is Sturgis and back from Michigan.

We did 85-90 from Wisconsin->Sturgis and same on the way back.

Seems like my level is between the add and full marks, I'll have mine in for the 5K soon, will definitely make it a point to ask them to note transmission and primary levels. Would love not to have to obsess about this.

 

thanks..please qualify the following statement:

"I've got an 17 RK built in 11/16 that has really only showed the issue twice and that was extend riding at 75-80, over 50 to 100 miles.. For me it seems to be getting better. "

the perception of getting better is due to less high speed/rpm long distance rides or__________________________?
I just can't envision the issue 'self resolving' over time based on any of the speculated root cause scenarios

 

Having never had one of these things apart, my post may be pointless, but from a purely mechanical perspective here goes. If the oil is traveling from the trans through the clutch push rod tube/passage to the primary, would it not be possible to put a seal into the tube to halt the flow. A small seal pressed into any end of the passage, who's ID was sufficient to seal against the push rod, and who's OD provided a press fit to seal against the ID of the tube, could stop any transfer, no? There may be design details I'm not aware of that negates this approach so I get that and assume the risk of even suggesting this. Fire at will, I'm wearing Kevlar.

 

The primary shares a common vent with the transmission, it vents through the pushrod passage. If they seal the passage they would have to vent the primary independantly which would require HD to go back to the EPA for testing to get the bike re-certified. This would be a fix for sure, but a costly one, they're probably looking for less expensive options at this point.

 

That makes perfect sense. Thank you!

 

I wonder if something like a Panhead trans vent screw tapped into an inconspicuous place on the inner primary would work?

 

If it's a venting issue and/or you wanted to plug off the pushrod passage with a seal or "O" ring it would. It's not a viable solution for HD though and it's a band aid for the real issue.

I don't personally think the issue is venting, I don't think the crankshaft main seal/spacer is the issue either. I know of multiple people that have had them replaces and are still experiencing the fluid migration.