Excessive crankcase pressure after build!! Need help

[41smith73]

I have a 2002 Road King with a fresh upper rebuild, all items new: 98" jugs, 10.25:1 Pistons, TW6H cams, heads ported heads with new breathers, larger throttle body,adj pushrods, lifters and the list goes on. All componets purchased from Scott Palmer( awesome guy) . My local wrench has years of Harley experience and it's got him baffled. We completed the recommended 5-6 heat cycles with no problems until I rode it home the other night( 3 city blocks) was idleing in garage and POP went the dipstick!! Oil leve is where it's suppose to be, Scott also recommended the 3rd gear 2000-4000 rpm and then back off do this several times to seat the rings, and it kept blowing out, I have a new dipstick coming but not real sure that's going to hold.
Any help would be appreciated..

[prodrag1320]

see if the lower end is full of oil (sumping),or the rocker bottom gaskets are on backwards (take the TB bracket off & see the theres air coming out the breathers)

[BUBBIE]

Are the breather seals in correctly ?... Like Kirby is saying too...  Also Check compression to see IF it is correct and Holding in Cylinders and Not Blow-By...



To Tighten the OLD or new dip-stick, Put a Big "0" ring fitted behind the Rubber Lip on the existing or new one, that should push out tighter and hold it in place.

signed....BUBBIE

[rageglide]

Wipe and dry the plug well after it's removed, wipe inside the spout too.  Not a cure, but will help with retention.

On top of the other suggestions.

Did you swap out the rubber vent line for the chrome tube?  As I recall the hard line presents more of a restriction than the stock line.

I drill the stock vent bolts to the largest size possible without totally compromising the integrity.  When installing them, don't overtorque them.   Better yet use a breather bolt and air cleaner assembly that allows you to use larger tubing.

[Sc00ter]

Breather internals upside down (umbrella)?  Rocker box gaskets end for end...

[Admiral Akbar]

Add.
Bolts without holes in the head breather holes.. Pinched vent lines.

[PoorUB]

Add.
Bolts without holes in the head breather holes.. Pinched vent lines.

This has been a common problem with after market air cleaners. Guys using the wrong bolts.

[rageglide]

Have to agree the easy mistake would exhibit that behavior...  Although I would think the plugged vents would show up at a much lower RPM.

[Admiral Akbar]

Have to agree the easy mistake would exhibit that behavior...  Although I would think the plugged vents would show up at a much lower RPM.

It probably depends on "how much plugged the system is..   May be something like one breather valve in upside down and the other OK.. Heck could be a hole in a piston.. Crankcase should see very little positive crank case pressure and only when the pistons are lowest.. Rest of the time pressure should be negative to ambient..

[41smith73]

We will start checking per posted suggestions tomorrow night, thanks guys for your opinions!!!

[1FSTRK]

If you have access, a leak down test would answer a lot of questions.

[Admiral Akbar]

If you have access, a leak down test would answer a lot of questions.

I thing it only answers one question.. Whether there is excessive leakage..

[41smith73]

Bingo we have a winner!!! Pulled it apart last night and BOTH breathers were Upside down. She's going back together tonight , thanks for all the replies and help!!!! Suppose to be in middle 60's riding weather here in IOWAN.

[1FSTRK]

Happens more often than you may think with the new style breathers, glad to here it was an easy fix.

[41smith73]

Me too!! Slept a lot better last night for sure..

[itsafatboy]

Mine did that once had the wrong rocker box gaskets for the SS covers , 

[06roadglide]

Happens more often than you may think with the new style breathers, glad to here it was an easy fix.

After getting a new set out of the box I can see this happening a lot.  They should include a diagram with them.

[Smarty]

Bingo we have a winner!!! Pulled it apart last night and BOTH breathers were Upside down. She's going back together tonight , thanks for all the replies and help!!!! Suppose to be in middle 60's riding weather here in IOWAN.

An old motor cycle engine guy taught me to take a black 3/8 rubber hose and push one end on where the a/c breather bolts go into the head and suck on the hose. If it pull air you are good, if you can blow air, it's no good. Always do that before I completely button things up.

[1FSTRK]

Bingo we have a winner!!! Pulled it apart last night and BOTH breathers were Upside down. She's going back together tonight , thanks for all the replies and help!!!! Suppose to be in middle 60's riding weather here in IOWAN.

An old motor cycle engine guy taught me to take a black 3/8 rubber hose and push one end on where the a/c breather bolts go into the head and suck on the hose. If it pull air you are good, if you can blow air, it's no good. Always do that before I completely button things up.

I have seen the guy I use do the same thing.
Something unknown comes in he does a leak down test, tells an experienced  builder 6-8 things with one test including the breather valve.

[Just Nick]

Where is fsg when I need some pics. I have not run across this and can not figure out in my head if you are paying attention to what you are doing how can you put the breathers in upside down.

[1FSTRK]

Check this thread
http://harleytechtalk.com/htt/index.php/topic,32991.msg337028.html#msg337028

[Just Nick]

Thanks I know what they are and look like they have been out for a few years now I just can't wrap my head around actually installing upside down but those pics help. So people are putting the unbrella on the bottom side and the sponge on top?