Ladies and Gentlemen,

I am new to this forum but hoping someone out there may have an idea as to what my engine problem may be... I recently purchased a very nice 2002 Dyna with 12,000 miles on it. Long story short, the bike is in awesome condition with quite a few thousand dollars worth of upgrades. I ran about 550 trouble free miles prior to changing the oil. I could not find the original owner (purchased it from a dealer in Ft. Worth, TX and had it shipped to Panama City, FL) and did not want to run it to long without an oil change.

Considering all the motor work done to it (95CI upgrade, cams, Mikuni 42mm, Vance & Hinds exhaust, S&S forged pistons, heads ported & polished with oversized valves and manual compression release installed by "Short Block Charlies", etc.) my best guess was the prior owner (who was the first owner) used a synthetic. I performed a few hours of research trying to determine the best oil to use and ended up putting Mobile One V-twin 20W50 in it with the same type of filter previously used (K&N). I have been an avid user of Mobile One in all my water cooled engines and have never had a problem. I read many rave reviews on the internet saying how good this oil performs and have found practically nothing negative about it.

The bike ran about 75 miles before I heard a low volume "screeching" sound one day during acceleration. I immediately backed off the throttle upon hearing this and held it steady with no more noise until I tried to accelerated again (not good I know... When something screeches it is usually screaming for oil!). I was only about 1000 yards from the house so I headed back home while noticing the illustrious "blue smoke" (kind of like the dreaded Microsoft "Blue Screen of Death!) from the exhaust.

When I got to the house I pulled the plugs and they were BOTH oil fouled (could two cylinders go bad simultaneously???). I have performed both a compression check and a leak-down check on the engine. Compression builds up to 178psi in the front and 180psi in the rear cylinder. It builds up immediately and all signs seem good according to my previous years of (automotive) mechanic experience. The compression ratio is 10:1. The leak down check was also good showing less than 9% leak down with 100psi in the cylinders... The only leak during this test was from the case breather (which is normal, it has to go somewhere eventually), nothing from the carb (intake valves) or exhaust (exhaust valves). My initial fear was shattered rings but these signs are telling me that's not it. Could I be wrong? Of course, but not likely in my humble opinion...

During my troubleshooting I also noticed I had filled the crankcase a little too much (about halfway up the marked area on the stick instead of only to the bottom as shown in the Harley Factory Manual for a "Cold Oil Check"). I drained the oil level back down, cleaned the plugs and fired it off again. Oil comes right back and fouls the plugs but I DO NOT hear any "bad noises" whatsoever... I wish I had a borescope to check the cylinder walls for damage/scoring but haven't found one to "borrow" yet.

I realize you normally go back and look at the last thing you did (oil/filter change). Could it be that this oil is just slipping right by the rings...? I also recently read that an "overpressure" problem (higher pressure is normal on a cold motor/plus the "overfill") can cause the crank roller bearings to "skid" instead of roll so my initial thinking was that this had created the screeching sound those two times during acceleration. The motor had not yet warmed up when this occurred and there was too much oil in it but not an extreme amount.

Anyway, my hope is that someone may provide some feedback related to this problem. I am a "total research" guy who doesn't mind constructive criticism or any other opinions that may help prior to pulling the heads and working my way down the motor to locate the problem.

Again, to me it just doesn't make sense how the compression/leak-down checks all show "normal" indications (in my opinion as well as the Harley Manual) yet the oil is still making its way into the cylinders... Could this simply be the oil???

Thanx in advance for any feedback forum members may provide!!

 

with only 12,000 miles could it be the rings have not set yet, meaning still breaking in the motor,what about the head breather, if not working could build pressure and bypassing the rings

 

Sounds like you have been as far as I have ever gone, built other engines but never a Harley. There is one other way for oil to enter the combustion chamber that comes to mind, down the valve guides. This would allow for good compression but still suck oil into the cumbustion chamber.

 

I don't think your problem is the type of oil. From your description I would guess the valve guides somehow aren't right. That doesn't explain a screeching noise but I would start there.

 

You're going to have to pull the heads to find out.
I will say this, the last time I heard "screech" and blue smoke used in the same sentence, a wrist pin clip popped out and tore up a cylinder wall. That wont explain fouling both plugs, but its the first place I'd look.

 

If you've overfilled the crankcase, it's possible that the breathers are pouring oil back into the intake which can result in blue smoke and oil fouling of the plugs. If you're running a Screamin' Eagle Heavy Breather you might never know it as it takes quite a bit of oil to leak out the bottom. I know from personal experience.

If compression and leak-down are good, I'd look elsewhere.

Additionally, I serviced my bagger last weekend. I switched back to Formula + from Redline Primary oil (cause my bike wouldn't burn out with the synthetic in the primary lol) and my clutch now "screeches" with the lever pulled in. But it grabs hard!

In my opinion HD clutches are pretty sensitive to oil choice...

 

sounds like you puked a bunch of oil down you cylinders from over filling , are you sure you have a twin cam oil filter ?

 

I have seen this before when my buddy over revved his triumph trident and put two small holes in the pistons. They were very small and it would idle and run a little but then oil would get past and foul the plugs. How high we're you revving it?

 

To All:

Thanks a bunch for your replies... Let me provide some further information relating to your suggestions.

Robtarra39: I am quite sure the motor is fully broken in. The reason I'd say this is because I had checked the plugs previous to this incident and they were the "perfect" light tan/brown color normally seen with a good air/fuel mixture. No oil fouling whatsoever! Also my research states that most engines are normally fully broken in within the first 3000 miles or so.

AFMM3 & nevil: I have had valve guides suggested to me by a student in the class I teach. I have about 32 years in aviation as an Airfame & Powerplant Mechanic/Manager and am now teaching others to "get their hands dirty". That could be a part of the problem but I like to use the process of elimination to be sure I cover all the bases before dismantling the motor. I should know more about the guides if and when I reach that point. I also agree that if it is valve guides I wouldn't think there would be a screeching sound...

kk6pg: I am still in the process of searching for a borescope to check the cylinder walls. I am pretty much PRAYING they aren't trashed. I also had someone mention broken oil scraper rings. This would also allow good compression but allow oil flow beyond the compression rings... The only factor I would find VERY strange would be how BOTH cylinders could fail simultaneously!

JCleary: The motor has S&S Reed Valves for breathers. During the leak-down test they were the only place any leakage could be heard (a GOOD thing in my opinion). Intake and exhaust were DEAD QUIET... There was just a "mist" of oil residue on the bottom of the breathers, something I am also quite sure would be "normal". Nothing pouring out so to speak.

sonnydaze: I am using the exact same filter that was installed on the bike when I purchased it. It is a K&N 171C. A clogged oil filter is mentioned in the factory manual as a possible cause for this condition so I am considering changing it out prior to motor dis-assembly just to be sure...

misfitJason: I don't rev my motor much past 3K or so unless I am "playing" which is rare. Even then, I never go beyond red-line. One of the mods on this bike is a Harley electrical tach so I monitor it constantly... 5th gear at 45MPH is about 2K revs. I barley get beyond this considering the local speed limits. Could I have burnt a hole in a forged piston? Pretty hard to do unless you get the motor VERY hot due to things such as improper heat ranged plugs or a very lean mixture (or combination thereof). Again, my purpose for now is to eliminate any causes "easily checked" (including a borescope inspection) prior to any motor tear-down.

I did come up with another question someone may know the answer too... The Harley manual states the following reasons for "Diagnosing Smoking Engine Or High Oil Consumption"

1. Oil Tank overfilled (checked this... Lowered tank volume, problem still exists)
2. Oil Carryover???? I have NO IDEA what they are talking about! Anyone have a clue on this one???
3. Breather hose restricted (has no hose(s). S&S reed valves installed)
4. Restricted oil filter (I'll check this out in the next few days)

The book then tells you to do the compression and leak-down checks before removing the heads to check an assortment of other items...

 

Oil carryover.....? Not a clue what that means.
S&S reed valves....could those have failed somehow?