Having owned Harleys since the 1980 Evo days,and reading all the issues folks are experiencing with the m8 motor, I have been wondering if the oil Sumping problem may be caused by the oil being aireated. Just thinking of what has changed over the last thirty years of Harley vtwin motor design. To me it seems the issues started with the counterbalancers in the new M8. Could it be as the spin they aireate the oil which the foats to the point it looses it's viscosity and stops it lubrication ability to the point the engine sezes ? Has anyone tried to eliminate the counterbalancers to see if that would end the problem? Even though I would love to own a new machine, I can't bring myself to purchase one until Harley resolves these issues. If it is the case design has anyone tried after market cases to see if they are part of the solution? I will sit out of the trade in my dealer offered me on a new 19 until The issues are resolved.

 

The Softail M8's apparently don't sump and they have two counterbalancers.

 

I don't know of any aftermarket cases. But I cannot imagine anyone spending that kind of money as an experiment. Either with cases or removing the balancers. If I wanted a 19 I would buy it. The new oil pump plate with the seal on the 19's might solve the problem. Or not. But the actual number of bikes that are sumping is likely very low. I have tried to make my 18 Heritage sump and can't do it.

 

The aireating problem is why they came up with the seal on that plate is sorta what I heard anyways. I hope it fixed the issue, I'm wanting to trade. LOL

 

Thanks. Had not heard that about the seal. My bike doesnt show signs of areation when checking the oil.

 

aeration?

 

I have an '18 FLHTKL. It hasn't showed signs of sumping. It seems to me that the folks who have been modifying are the ones having issues. Just a thought, as I don't recall reading about stock having issues.

 

There are stock bikes that sump, but there does seem to be more cases of sumping for people who have modified their bikes.

 

I've owned HDs that were built back in the 40s. Rebuilt ones built in the 30s.

By definition, dry sump oil systems aerate oil on the return to the oil tank. It's not an issue. All HDs from about 1933 on do it. Newer ones are a bit more because they push much more oil than the predecessors. As long as the oil is hot enough to loose viscosity and allow the bubbles to separate, it's not an issue.. Just look at what HD does to the return path of the motor oil to the oil tank. Older bikes had tanks that were taller vertically to separate the bubbles.

How come the tc softails didn't have this issue? My xr400 spins to something like 8500-9000 without sumping and it has a counterbalancer almost exactly the same configuration as the M8. BTW HD has always pretty much been 20 to 30 years behind the rest of the MC industry.

The real issue is close and has to do with the scavenge system. It more along the line of pressure variations in the crankcase causing the scavenge pump to loose prime. Same issue occurred during TC development but was fixed before product release. Once the oil cannot be suctioned out of crankcase, the motor simply overheats and the oil breaks down. Failure occurs. This is the result of sumping.

FWIW some motors have eaten oil pumps. We don't get to see why (HD coverup) but my bet is that there is an issue with the pressure relief valve in the pump. I suspect that they are sticking, causing a loss in oil pressure and resultant engine damage. Again it's not from aeration.

 

Thanks guys for the responses.If the issues is truly something to do with crankcase venting as Max is suggesting, I would think Harley would be working overtime to correct this. Years ago cars had a simple primary crankcase vent in their valve cover, the PCV valve which vented the crankcase. Could the solution be that simple ? We use to install new ones all the time in my dad's auto shop in the 70's it was part of a tune up back in the day. Maybe the fix is simpler than we think.