These thing can seep some assembly oil that's on the outside of the o ring for a while. Sure that's not what you are seeing? When appart, make sure the dowel rings have been installed too. O rings are virtually idiot proof and to have it happen twice means it either residual oil or somethings missing. Don't add any sealer, but do put a very light smear of oil on the o rings so they position themselves without rubbing the contact areas. Before doing any teardown make sure the oil is in fact from that area and not from somewhere else ending up there and fooling you.
Ron

 

DON'T USE A BONDING AGENT!! NO!
There's an "O" ring that seals everything up in there. Make sure that the "O" rings are on the oil return dowels and everything is clean on reinstall. Base of your cylinder may need to be lapped if it's slightly warped. Take it to a machinist to check it.

 

Thanks guys
My cylinder bases must be warped I don't think the dealers could have blown it twice with the o rings .
Maybe I have the same problem as the CVO 110 models where having with there leaking bases.

 

let me guess it is either weeping at the back of the rear cylinder and/or the front of the front cylinder. both clutch side. I know some very smart people who use just a smear of sealant at the base around the oil return dowl. that little oring seems to shrink sometimes. If it is not weeping too much just leave it. there is no pressure there just gravity.

 

Correct on both cylinders on clutch side.

 

Hogbag I had the same issues when I first did the 103 build I followed (HD procedure). When I did my heads I followed the correct Head torque procedure ( Cometic) and no leak this time maybe they just rushed the job and didn't torque it correctly

 

After how many miles did the oil leaks develop? Maybe, just maybe the dealer did the job correctly. Per the manual prior to torquing the head bolts the threads and surface area where the bolt meets the head need to be lubricated with oil to ensure proper torque is achieved. Residual will leak down into the cylinder stud holes and seep out between to highly torque metal mating surfaces (going to take time to leak all out). Granted maybe they got carried away with oil. Very similar issues with the SE110 with the cylinder liner moving upwards breaking the seal of the gasket and allowing oil from the oil return dowels and combustion contaminates to seep into the cylinder stud holes, thus appearing as a base seal issue when the problem is inches higher at the head gasket. No guarantees this is your issue, but a very good possibility. I see a little oil at the base, I give it a little time and see what come of it.

 

The first time it was around 1000 k's this time around 6000 k's. If I give the bike a hard run it will leave a black oil line from the rear cylinder where it runs across crank cases. If I just cruise around there's a weep around the base. I change my engine oil regularly and its never black but the oil that weeps from the cylinder base is always a darker color than my sump oil.

 

Any more clue's and how to stop this leak I would hate to have to strip the top end for a forth time

 

is it warm in Australia this time of year? If it is try running straight 50 weight and see if that helps. can you post a photo to show how bad the weaping is?

 

It doesn't make any difference hot or cold it still weeps. The photo as requested

 

I'm thinking your machined surfaces are not mated evenly. Ever so little out of spec. That's my idea anyway!

 

try pulling the case bolt out and see if any oil comes out from behind the bolt head

 

over heating can "create a leak" do you or have you done any long slow speed riding, ie parade of some sort? the studs can stretch and you will loose your torque.... when you remove heads see what the torque was. if there all the same i think 42lbs then you can disregard that possiblity. not going to defend hd but id be shocked if the surfaces were not true.

good luck, tearing a top end down is fairly easy, just pay attention to detail, get torque specs, and be very clean

 

There is also a slim chance you could have porosity on the outside of the o ring as well channeling oil between the cyl base and case. Dye pen will find it, but an effort needs to be made to look for any possible details that could cause your problem. Just slapping in another o ring clearly don't cure the problem.
Just did a top end on a Da Zon 175cc dune buggy and when running a tiny pinhole was feeding oil out from the middle of the head. A really good cleaning and wicking grade loctite cured it, forever. Prior to teardown for leaking head gasket there were lots of little black dried oil spots sitting on the engine. Couldn't come up with an answer as to how they got there until discovering the pinhole on the rebuild.
Ron

 

one draw back to the silver cases. on black cases you would not notice it. It looks pretty minor but that is easy to say about someone elses problem. If you have the ability I would just get some Wurth brand hylomer and left the cylinder and put a thin coat around the mating surfaces.

 

There is also a good chance they didn't put the little green o-rings part number 11273 on before the cylinders.

Don't laugh..HH in Adelaide have done it and more than once.

 

Thanks for all the replays
My bike had a engine crank case oil leak that started at 10000 k's a black oil puddle behind the rear cylinder . The first dealer split the crankcases to bond them and install the 103 slugs 54 cams . 1000 k's latter it started leaking again at the cases and both cylinders. Second dealer split cases again to seal them. 6000 k's the rear cylinder is leaking and the front cylinder is misting around the base.
I will check all the suggestions and tips given on this thread.
If there is oil behind the bolt in the case I won't be splitting the cases again unless the crank scissors.
I'm guessing it wont be that long because I will be fitting 82cc stage 2 heads to complement the 54 cams and 103 slugs around 10.2.1
Merry Christmas to everyone and thanks again for the tips

 

Seen a few engines that had a case issue. Small casting hole that would leak oil. If o rings are in cylinder is flat, you case use hylamore ( spelling??) aside from welding the case have done that and re cutting the o ring groove or replacing cases the sealant is an option. Had one here about a year ago that was a leaker. Customer bought it new and HD did the work a few times but it never stopped leaking. I found the pinhole , drilled it , and tig welded it up. Fixed without splitting the cases. A bit of a PIA to keep the lower end 100% clean while you are doing all of this. But it can be done, on others that leaked I could not locate exact location of issue, so sealant was used. several years later bike is still not leaking.

 

This condition is more common than you think with all castings. None are porosity free, but every now and then it will show to the outside as a leak if in the right place. I weld aluminum all the time, and it would be my last choice to fix it. Firstly it anneals the parent metal making the zone softer than the surrounding area. Then there's the distortion problem. With welding comes distortion, no way around it. While it maybe only .002 in that spot, that's huge on a cyl deck. My proceedure with wicking grade loctite is simple and permanent.
Whipe all oil off with brake cleaner until spotless. Heat suspect area with a heat gun. This will expand any fluids trapped in the porosity and will ooze out showing the location of the leak. Mark the area with a marker and continue to heat and blow until no more oil appears. Let it cool. Clean again with brake cleaner and brush the #292 over the problem zone. The object is to keep the area wet and allow the loctite to creep back into the voids. Forcing the fluid back and forth with your finger will jam it in deeper, but not always possible depending on location. A small paint brush, going back and forth works well too. After about 15 minutes whipe off the excess and apply light heat from a heat gun to expand and cure the loctite. For me, this has been a 100% success rate on many applications.
A few years ago we machined a huge water pump for a US nuclear plant. On the 200 psi water test a small leak was pissing a stream of water out. Repeated attempts of welding this huge casting failed. The only other approved method was loctite and it was an instant success. That was 15 years ago. Sleep tight.:redrolf:
Ron

 

does the locktite 292 stain the black cases?

 

The area in question for the op is likely on the machined surface or in the oring groove. and will not have any effect. In a liquid state, like on the cases it must be whiped off with a damp rag with a touch of brake cleaner, lacquer thinner or whatever once sufficient wicking time has occured. The extra on the outside has no bearing on the repair but is part of the application process or necessary mess needed to get the sealant into the pinholes. Any loctite remaining on any outside surfaces must be removed because even though anaerobic, heat from the engine will cure it to a really hard substance . Almost impossible to remove if it heat cures without damage to the powdercoat since it will bond to it's rough surface. If cleaned off while in a liquid state, I've seen of ill effects on the appearance of the black powdercoat.
Any repairs should be done on a cold engine. This increases wick time and more clean up time for the surface. Try this on a hot engine, you will be pissed beyond belief.
Ron

 

I checked with the locktite dealer and he said they only make 290 and 294. he said 290 was for low heat apps and 294 for higher heat applications.

 

My mistake. I believe I mentioned 292, which don't exist. That's what happens when you have a stash of bottles and the numbers get confused and post without looking. I used the 290 with success in engine temp heat with no problem, since around here it's better than 40$ a bottle last time I bought some. 294 is a higher rated temp and if I were to buy again it would be that one, although unless you are trying to seal up an exhaust pipe the 290 still works. There is also this, that's more specific to the job.
http://www.henkelauto.com.cn/automo...m.cn/automotive/Products/Sealants/Product+Catalog/default.htm-ProductId=113.htm
Ron

 

Doesn't it just piss you off to no end to have this happen and there seems no justifiable answer? All that time and money spent. Yep, I sure do know the feeling...

 

Had a phone call on something like that, Guy was using the the heat process on gear drive cams, well he heated the outer gear as well said it slipped right on. He puts the red loctitie on the bolt gets it in about 4 threads and it stops. He cant figure it out. I asked how hot did he heat the items. He was doing this in welding gloves. WOW!!! With heat it locks up fast.

 

This was extreme. I have assembled parts that are bond only and a mild warmup with a heat gun will set the parts quicker. Use to make hydraulic bow stabilizers years ago when involved in competitive 3d archery. Made the mistake of using loctite primer/acticator once. 680 loctite cured before I could put the parts together. Live and learn.
Ron

 

My 2000 RK had a rear cylinder base leak that I took back to the dealer twice with less than 1500 miles. They finally fixed it. Now with over 105000 miles on the bike, I know how. I was upgrading to a 95ci and pulled the jug to find sealant - likely Hylomar. After about 100 miles with the new build, I am getting the same oil weep at the rear cylinder. I will give it a few more hundred miles and see if it gets better or worse, but expect I will have to use sealant again or try the Loctite 290 if I can find the source of the leak. Afterall, the sealer seemed to work when the dealer did it.

 

Ron

You are a PIMP!!!

 

Prostrate treatments have come a long way, you know?
Ron