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[Dave]

When I had the Screaming Eagle Air Cleaner installed one of the things I had my dealer do was run the breather hoses into the air cleaner (holes in Screaming Eagle Air Cleaner backing plate).  Recently I changed spark plugs and noted the front cylinder was pretty wet with oil and fairly fouled. Exhaust pipe from front cylinder exhibited the same oily deposits while left pipe was dryer in comparison (I suspect due to higher rear cylinder temperature thus able to burn the synthetic oil off) Oil consumption was approx 1 qt in 700 miles.  Oil was apparent in the air cleaner and throttle bore.  Since removing the breather hoses from the air cleaner the exhaust seems less oily, used no oil in last 480 miles.  I will still check the plugs and dealer is going to perform leak down and compression test.  Has anyone else had this experience?

I am thinking of installing Doherty Power Valves and after I sell my first born son perhaps TP rocker boxes since they claim to be able to eliminate oil from the vents.

[PCC]

Dave, funny you should ask.... Here's what I have found with the 103" motor and Harler Twin Cam's in general.

The 103" uses cast pistons and rings stock. The ring are thinner than the 95" motor's due to the thinner piston to accomodate the 103's stroke of 4.3. Thinner rings equals a greater chance of leakage, blowby, etc.

Harley cylinder's are notoriously out of round from the factory. I have recently changed pistons in my SEEG and the cylinders were .0025 out in varous locations throughout the bore. The service wear limit listed by Harley is .0020!!!!

Combine these things with increased cylinder pressure from more fuel and air in the chamber due to better cams and if a particular cylinder is on the edge you get oil in the chamber. Your situation with oil fouled plugs, oil in the throttle bore and deposits in the exhaust are all tell-tale. Additionally, poor breathing can contribute to this situation and, of course, the oil in your throttle bore could certainly come from running the breather hoses to the air cleaner.

I have seen situations where oil actually leaks from the exhaust ports due to the aforementioned piston/ring situation. If your predicament clears up by running the breather hoses outside then there's nothing to worry about...If it doesn't, these are some other questions to ask.

I run a breather crossover (old style Screamin Eagle) from the breather bosses in the heads and a long piece of Earl's #6 braided hose all the way down between the motor tranny and attach to the frame. it looks OK and gets the blowby away from almost everything. GOOD LUCK!!!!! [smiley=cool3.gif]

[Dave]

PCC - Thanks for the information.  After I have the leak down and compression test done I will post the results.  Do you suppose changing to forged pistons would make a difference?  If the leak down/compression test fails I will use the opportunity to upgrade parts rather than staying stock.  For now I just want reliability for the ride to Sturgis in August.

Cheers!    [smiley=huepfenjump3.gif]

Dave

[rugbyprop]

Dave, interesting post.

I just posted this under "Using oil" yesterday in the general CVO discussion area. I sense it may be similar to your situation. Although I have not witnessed any residue yet, but was told by the dealer if I approached the 1 quart in 1000 area I would see the residue.

Here is what I posted:

Just wanted to hear any feedback on Oil Usage. During my first 750 miles on my 04 SEEG I thought I used about 1/2 quart of oil. But I could not be sure because I really did not pay close attention to the "cold Check" vs. Hot Check of the oil and could assure it was completely full from the factory. Took it in for the 1000 mile and thought I would watch it closer.

[PCC]

The forged piston question is interesting not because of the pistons themselves...but because the rings which come with the Harley pistons are moly rather than cast. A lot of folks swear by cast rings and think that forged pistons are probably better. My belief is that the "blueprinting" involved with cylider bore tolerances and ring gaps...etc. is probably more important...it's just a judgement call and expensive unless you do the labor yourself. Something else that might be more imporatmt for you though is the synthetic oil issue. i don't know what brand your using...but you might try switching back to petroleum based oil for a few thousand miles and see what happens. that synthetic stuff is slick and will leak when the regular oil won't.

By the way...  I have found no other manufacturer of forged 103" pistons besides HD. The strokes for alll of the other big inch kits are different. I believe Arias makes the HD pistons. [smiley=beerchug.gif]