I must really be lucky then. My completely stock 2018 114 Fatbob is in dealer shop waiting for new oil pump. 1800 miles. It can, and does happen to anyone.

 

If you read my post, I was referring to how much oil was in a TC sump. On all these sumping issues on the M8, no one seems to know and I also do not. Not even sure if a M8 still has some splash lubrication like a TC.

However, ever time I ask no one else that is really crying wolf knows either.

I am not an idiot. I spent 46 years as a engineer and have rebuild numerous engines over the years.

However, the M8 is still a mystery to me and I do not have a service and electrical diagnosis manual yet. However, am working on it.

What does it say in a service manual for the M8 under engine oiling that describes the details of how it all gets lubrication.

Also, the FP is asking about a used bike that no telling what someone had done to it. And if modifyed why usually they are getting rid of it. It's a real crap shoot to buy any used Harley in my opinion.

 

Here is what I know based on my own experience. I had a stage III installed on my 17 RGS prior to delivery. The Moco came out with a SB in regards to sumping and gave test instructions, stating 3 oz in the sump was the limit. I tested my bike and had only a dribble left in the sump. Thought I was golden. Several Thousand miles later with 15,500 total miles on the bike the engine had sumped and had a bad cam.

I traded that bike for an 18 RGS and am leaving the internals stock. There is an updated SB that changed the amount left in the sump from 3 to 6 oz.

I will also say my 17 never over heated, never had loss of power and as preventive maintenance was scheduled for an updated oil pump that was not available when my stage kit was installed. A week before my appointment the engine developed a bad rattle and that was that.

The M8 is a top performer, I love the engine. MY plan is to ride this 18 and when the MOCO figures out the issue I will get my bike updated.

We should all be looking to the new bikes built after 10/17 as they have the latest pump, hopefully none of these bikes fail and we can move off this issue.

Good Times.

[ one more thing ] With The stated allowance between zero and six or more ounces of oil left in the sump at any givin time, checking the oil can give weird results. Both of my M8 bikes have had oil level weirdness. If I want a good reading of the level, I let the bike Idle a couple min before shutting down after a ride. That allows the sump to clear and return the oil to the pan.

 

Um no. Silly

 

Every Harley service manual I have owned has documented this.

 

????. That was my question. I have manuals all the way from the 40s to 2014. 70 + of them. However, no M8.

Least 3 oz has now been said. Obviously, there is not a lot of splash lubrication going on there. How does your M8 service manual describe the oiling.

Thanks 6guns for the info and not calling me an idiot. Not quite as smart as PF Wiz but all the ships I built for him, you would think he would give me some credit...

 

This and the fluid transfer issue is why I'm not upgrading to a 18 RGU yet.

 

Unless the information is positive, right?

Using your logic, all those reports of reliable bikes must be unreliable LOL.

But, who cares if there are problems anyway? After all, that's what warranties are for.

 

I misinterpreted your point. I thought you were saying that its damning that the M8 service manual documents the oil flow, meaning it must be problematic if they feel the need to document, I was just saying all of he manuals document oil flow, so its not an indication of anything

 

My current theory for sumping is that the faster the engine spins, the more oil collects in the sump.
Those who have Stage III or Stage IV on their bikes, are probably more likely to spin the engine up higher in the RPM range more frequently than other riders, because that's where all the improvement in performance is found. Especially in Stage IV.
Steve Cole says it can happen to any bike, including stock. We've seen reports of it happening to stock bikes. We've seen reports of it not happening for 15,000 miles, then suddenly happening. What could have changed? My guess is some extended time in a higher RPM range.

If I'm not mistaken, KeithHu is the one who said he can make it happen pretty much at will, pulling out and passing a line of cars. If it's a good long run at high RPMs, maybe that's what's happening. Could have been someone else though.
My guess is that any time spent in the high RPM range is probably causing some buildup of oil in the sump. If it's only a little, then the system can clear it, and you have a problem-free bike. If you spend too much time in the high-RPM range, then the oil accumulates faster than the pump can clear it, reaches to the crankshaft, and you get the sumping symptoms of frothing oil, loss of power, and engine damage.

My guess is that those of us who have never had the problem, probably don't spend much time in the high-RPM range. I know that in general I don't really exceed 4000 RPM very often, usually only in a quick dash up the freeway onramp, and most of my riding time is at under 3000 RPMs backroad cruising. Under my theory, that should not lead to any sumping issues, as any accumulated oil during high-RPM maneuvers should be pretty slight since high-RPM is infrequently encountered. I have the torque cam in mine, so the main power gains are down low, under 4000, and that's where I usually ride.

Those with Stage IV especially, all the power gains come at 4500 RPM+. If I had a Stage IV, I'd ride the hell out of it at 4500-6000 RPM, that I can guarantee you. And, probably not coincidentally (under my theory), Stage IV bikes are more prone to sumping. Not necessarily because it has Stage IV installed, but more likely because a Stage IV bike is more prone to being ridden more frequently at higher RPM, thus resulting in more oil collection in the sump.

We had a post on here yesterday, someone said that riding at 5000 RPM would cause the bike to sump, period. He said he could ride all day long under 5000, no problem, but at 5000+, it'd happen every time. Now, that could be just his bike, or it could be the key to understanding the whole sumping mystery and why it happens to some but not all of us, and that maybe it has nothing to do with Stage III or IV, etc.

I guess we'd need a guinea pig to verify it for us. I know I don't want to try to force my bike into a sumping situation, but if there's someone out there who wants to test the theory, I'd think you'd want to do something like, say...

1. Check the oil level.
2. Go do 15 minutes of normal riding, keeping the RPMs below 3000.
3. Check the oil level.
4. Go do 15 minutes of banzai hell-for-leather riding with RPMs as high as you can keep 'em.
5. Check the oil level.

If step 5 shows a bigger oil level change than step 3, then ... yeah, high-RPMs probably result in oil collecting in the sump and not being properly scavenged out.

If it can be demonstrated that this happens on a never-sumped-before bike with repeatability, then we would have documented evidence of a fundamental design flaw in the M8, and that the M8 doesn't meet the basic fitness-for-purpose test, and the MoCo would have to fix it and recall all bikes so affected.

Simultaneously, it should pretty much demonstrate to riders what they need to do to avoid the sumping issue, so they don't necessarily have to fear getting stranded in the middle of the desert by a random chance event.

I'm not a mechanic, I'm a computer programmer who spends my days trying to figure out what went wrong in programs, piecing together the evidence, and then fixing the problem. So I may be totally off-base here, but it seems reasonable to me that the triggering event is high-RPM operation.