Rear Head Check Valve-Gas Man

mcgroom

Well-Known Member
I have 02' 107" S&S. I actually have a hose that T's into the backing plate from the top of my heads. I also have a line the runs from the bottom of my rear jug into my backing plate.

Which one should I attach a filter to and what should I be plugging.

Was this before the EPA stepped up the standards?

I get some blow by as well.
 

Gas Man

Cool isn't cheap
Calendar Participant
You have a different breather setup than the newer dogs. I think Ray or Sul can help you with your setup.
 

dogvet

Banned
proflyer wrote "run the rear hose straight across to the front head, since it sucks and the rear blows....any thoughts on that guys"
Not a good idea. The engine would have no way to vent off positive crankcase pressure which could lead to a couple of interesting problems.

1. Positive and negative pressure is how the engine transfers oil from the flywheel case back to the cam chest to get the oil back to the oil pump and ultimately back to the oil tank. the accumulation of oil in the flywheel case will cause an accumulation of oil the will increase drag on the flywheels and throw excessive oil up into the cylinders (will probably start burning oil).

2. when crankcase pressure is allowed to build up, oil will start leaking from the most interesting places (base gaskets,cam cover, engine seals, case halves or just about anywhere else on the engine.

On the earlier engines (04 and earlier) the bottom end hose can be removed from the air cleaner and re-routed below the engine...but use a filter because there is positive and negative pressure there. The negative pressure makes the hose a little vacuum cleaner, great for sucking up sand when cruising beaches!

the top end breathers can be re routed but should be run thorugh a breather valve (like Spyke, Wimmer, Doherty).
On 05 and later bikes, the hose from the rear head can be re-routed, but the small hose from the manifold to the front head should either be left alone or plugged off at the manifold and front head.

this will increase oil pressure at low rpm where you really need it.:zz2cents:
 

Fibersnake

Banjo Playing PsychoBilly
Dogvet

I agree and I thought that was what I was basically saying in regard to proflyer post about any thoughts.

Personnaly I leave it stock and the few times I get on it enough to show some blow-by and a sheen, I just wipe it off and check levels. Very seldom does this occur and when it does only when I give it the old yellow light push.
 

PROFLYER

SWOLE
I ran it down to the frame and put a little filter on...so, should we all plug the front head and manifold? I like more oil at low rpms for sure!
 

mcgroom

Well-Known Member
On the earlier engines (04 and earlier) the bottom end hose can be removed from the air cleaner and re-routed below the engine...but use a filter because there is positive and negative pressure there. The negative pressure makes the hose a little vacuum cleaner, great for sucking up sand when cruising beaches!

QUOTE]

That is what I thought. Now when you say below the engine, does that mean I can not lay the filter on the plastic pan near the horn at the base of the block or do you mean that I literally have to get the filter below the engine/frame? I can do either, just want to do it right.
 

Gas Man

Cool isn't cheap
Calendar Participant
I know when I tried it on my TP boxes it blew the cap off the head within a mile... spit oil all over the place.
 

TheCleaner

Member
Nice thread. Good info...just put a spike on mine to try out and I will route mine to the ground also. Can I put a filter on the end of it?
 
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lee

Well-Known Member
Nice thread. Good info...just put a spike on mine to try out and I will route mine to the ground also. Can I put a filter on the end of it?
no need to I don't think. I seem to remember John Sachs saying not to put a filter on. I certainly haven't got one on mine.
 
Okay guys been doing extensive reading on this as it is 2 am here. I have an 04 and I am getting ready to mount the D& M spike. Understand the rear crankcase breather needs a filter easy day. The only thing I dont understand is the part with the black hose that sits on top of the Carb. how does this route?
 
I have a 06 with a 117" and the D&M Spike. On mine the rear crankcase hose is routed to the ground (no filter) and the front cylinder hose goes to the intake.
 

Raywood

The Pirate
Staff member
Calendar Participant
Troop Supporter
Okay guys been doing extensive reading on this as it is 2 am here. I have an 04 and I am getting ready to mount the D& M spike. Understand the rear crankcase breather needs a filter easy day. The only thing I dont understand is the part with the black hose that sits on top of the Carb. how does this route?
Paul, the 04 and older bikes use the Evo style breather system. The 05 and newer use the Twin Cam breather style.
Your bike breathers out of the two head bolts that the carb is mounted to. So you will either need the breathers that DM supplies or others like Wimmer. You can see them here: 90° Basic Build Kit


Those of us with the newer models don't need these breathers so just remember you need the Evo style breathers! Another way is to use the existing breather lines and route them together then to the ground as you see in Gas Mans thread with a filter on the end. Many ways of doing this with your model. I've seen them routed to a Jim Beam bottle under the carb!



:cheers:
 

Attachments

Ray, Thanks you got it. I received the filter and choke yesterday still waiting on the breather support bracket that you displayed. Just wanted to make sure I had all the parts and pieces before installing.
 
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