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Discussion Starter · #1 ·
I have some scoring in the breather gear housing and on the plastic breather gear, I will buy a S&S steel breather gear.
However how bad does the scoring in the breather housing, have to be before needing it reamed out for the bigger breather Gear, do the cases need splitting to ream?? The scoring is there but doesnt seem to be to bad.
The Plastic breather gear seems to be a good fit in the housing, not to tight, not to loose.

Another question, when checking the cam end play clearance, in the Harley manual it says install 4 bolts in cam cover and check the clearance. Do i subtract .006 ( for compression of the gasket after torquing) off this like it describes to do when checking the clearance on the breather tube when using a straight edge and gasket?
Or is the clearance range in the book, for camcover not torqued?



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Install a real breather gear and if it rotates smoothly I would say you are ok.
Big If.
You need a real one anyway, no money lost . ( no plastic crap)
End play? I measure through a tappet hole and skip the guesswork.
 

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The damage you see is evidence that steel debris has been through the breather... indicating a failure of some kind has previously occurred...
Harley used the plastic breather to minimize the damage done to the engine case,,, in the event of a component failure in the cam chest...

Yes, the cases must be split to effect a .030" oversize breather assy..
 

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Discussion Starter · #4 ·
Install a real breather gear and if it rotates smoothly I would say you are ok.
Big If.
You need a real one anyway, no money lost . ( no plastic crap)
End play? I measure through a tappet
Install a real breather gear and if it rotates smoothly I would say you are ok.
Big If.
You need a real one anyway, no money lost . ( no plastic crap)
End play? I measure through a tappet hole and skip the guesswork.
Yes im measuring through the tappet hole, just not sure if i torque the cam cover before measuring.
 

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Yes, cause it will compress and change the measurement.
Beware- if you rip a gasket going on and off and use a different gasket this can change the measurement,
Because different vendors make them in different thicknesses.
Next
In my opinion, if your new steel breather spins freely in there, (and not lose either) you are good to go as all it does is direct the crankcase airflow.
Not much of a load on it.
 

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Discussion Starter · #6 ·
The damage you see is evidence that steel debris has been through the breather... indicating a failure of some kind has previously occurred...
Harley used the plastic breather to minimize the damage done to the engine case,,, in the event of a component failure in the cam chest...

Yes, the cases must be split to effect a .030" oversize breather assy..
Ok, it was the same owner the past 20 years he hasn't had any work done on the motor. But it definitely has had someone in there before e got it, i found the front pushrods are adjustable alloy, whilst the rear are the original non adjustable steel ones and the cam bearing had been changed to a torrington.

Decisions decisions, if to just try the steel breather in std size.
 

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Discussion Starter · #7 ·
Yes, cause it will compress and change the measurement.
Beware- if you rip a gasket going on and off and use a different gasket this can change the measurement,
Because different vendors make them in different thicknesses.
Next
In my opinion, if your new steel breather spins freely in there, (and not lose either) you are good to go as all it does is direct the crankcase airflow.
Not much of a load on it.
Ok thanks for the advise
 

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We all have opinions, right?
Terry is a real mechanic (i think)
I am not.
i worked in a Harley shop once in my life, and dont know everything.
But nothing much has changed.
The things i work on are way different than Harley.
If it was an aircraft, I would say inspection time.!
But-its not....LOL
It's just a slow-turning, archaic, POS tractor engine with some chrome on it.
I don't think you will get much worse off as whatever went through it prolly was a long time ago?
No offense to anyone that disagrees with me and is a democrat......argh argh argh
 

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My indie taught me what tall terry says. The OEM breather is plastic because it is sacrificial to help save the case.
I guess if it wasn't being bored out, I would put a new OEM plastic one back in.

Question for the engine guys: Would that be OK?
 

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Well the opposite happens as the plastic collects the crap, it gets embedded in the plastic and this is what happens.
Another one of Harley's bad ideas.

Plus they warp, lose teeth and nothing good ever happens because of them.
 

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I have some scoring in the breather gear housing and on the plastic breather gear, I will buy a S&S steel breather gear.
However how bad does the scoring in the breather housing, have to be before needing it reamed out for the bigger breather Gear, do the cases need splitting to ream?? The scoring is there but doesnt seem to be to bad.
The Plastic breather gear seems to be a good fit in the housing, not to tight, not to loose.

Another question, when checking the cam end play clearance, in the Harley manual it says install 4 bolts in cam cover and check the clearance. Do i subtract .006 ( for compression of the gasket after torquing) off this like it describes to do when checking the clearance on the breather tube when using a straight edge and gasket?
Or is the clearance range in the book, for camcover not torqued?



View attachment 272772 View attachment 272773
The spec on end play is so wide that you can ignore gasket compression, so long as you are not right up against the limits. Gear lash is the one you want to pay attention to.
 

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My bike is an 85 model, i dont think there meant for the earlier evos.

Guys are running them on all eras of the Evo and shovels as well. Discussions around these are sort of like discussions abut oil. Lots of noise but very little signal. FWIW, I ran one for a couple years on A Delkron engine case that vented through the heads and engine case. All of the online arm chair quarterbacks said thee sky would fall if I ran it. I never did see the sky fall. It was in the motor (Taj-Mak-Motor) when it was pulled for the twin cam conversion (Smack-A-Hoe).

IME, this is a perfect application for this reed valve. Don't split the case, don't hone anything and instead of buying a new plastic or metal breather gear as has been suggested, just buy one of these and be done with it. But watch out for falling sky.
 

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You wouldnt have any tips on what size and type hone i can buy to do it?
I use an old wheel cylinder hone that has caliper stones on it. The wheel cylnder hone will go small enough to fit the hole, and the long stones don't hang up in the hole.

This is just a photo I grabbed off of the net, but the long stones are shown laying by the hones. You should be able to get a hone and the long stones almost anywhere that has a Lysle tool rack. Or Amazon. You want it to fit the hole,and have about a 2 inch stone.

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Something like this would do it

Hone

You also want to use a plastic gear. They are more forgiving of imperfect bores.
 

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Discussion Starter · #20 ·
Guys are running them on all eras of the Evo and shovels as well. Discussions around these are sort of like discussions abut oil. Lots of noise but very little signal. FWIW, I ran one for a couple years on A Delkron engine case that vented through the heads and engine case. All of the online arm chair quarterbacks said thee sky would fall if I ran it. I never did see the sky fall. It was in the motor (Taj-Mak-Motor) when it was pulled for the twin cam conversion (Smack-A-Hoe).

IME, this is a perfect application for this reed valve. Don't split the case, don't hone anything and instead of buying a new plastic or metal breather gear as has been suggested, just buy one of these and be done with it. But watch out for falling sky.
Ok more food for thought, whats the worst that can happen with the reed valve, or the reason the sky could come falling?


Whats a Taj-mak-motor?
 
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