Please explain the plastic breather thing.
Road Master
Joined: Aug 2010
Posts: 1,205
Likes: 18
From: SE Michigan
Really?
Well, those arguments go in line with what my Indy said, and why he recommended getting a steel one. But this stuff is to be expected in my life. There is never any easy fix for anything. When you make a simple decision to replace the crappy cam bearing Harley so foolishly put in, all the sudden a 15 dollar cam bearing becomes a bearing, then a cam, then adjustable push rods, then lifters, then a breather.... and 15 bucks all the sudden becomes 20 or 30 times the initial cost. 
I'm thinking metal on metal where oil is a lubricant would be better than plastic on metal as long as the oil is present. Afterall, pistons and barrels are "metal on metal" and they survive just fine. Extreme heat, mechanical motion plus chemicals in the oil have to be hard on plastic?
Novice
Joined: Jul 2014
Posts: 21
Likes: 1
From: Ormond Beach
Plastic Oil breather gear... Replace it now!
I tell everyone with an EVO... Change to a steel breather gear!
(I've known it to happen to other EVO Harleys!
Harley EVOs are easy to work on, but did you know that the oil gets pumped through the system and then goes through the oil filter?
The Twin cam is the first Harley engine to send oil through the Oil Filter before it goes through the engine?
Banned
Joined: May 2018
Posts: 4,576
Likes: 978
From: Viet Vet, crossroads
OK here is the fulcrum and the catalyst -
Clue one-
Several vendors offer services to fix the bore where the cheap plastic breather was.
Clue 2-
The bore never had to be fixed for the EXPENSIVE steel breathers.
So there lyeth the answer.
Bean counters and money saved.
The cheap plastic ones or the expensive metal ones?
HD elected to go cheap, again.
I have never taken an Evo part that did not have damage from the plastic POS.
Get rid of it.
The next question is - go with a reed valve rather than a timed unit?
Remember, HD never had issues until they started changing what worked for the last 100 years.
Go spend the big bucks on a real breather and be done.
Clue one-
Several vendors offer services to fix the bore where the cheap plastic breather was.
Clue 2-
The bore never had to be fixed for the EXPENSIVE steel breathers.
So there lyeth the answer.
Bean counters and money saved.
The cheap plastic ones or the expensive metal ones?
HD elected to go cheap, again.
I have never taken an Evo part that did not have damage from the plastic POS.
Get rid of it.
The next question is - go with a reed valve rather than a timed unit?
Remember, HD never had issues until they started changing what worked for the last 100 years.
Go spend the big bucks on a real breather and be done.
Seasoned HDF Member
Joined: Jun 2015
Posts: 10,284
Likes: 7,766
From: West Central FL
I believe the theory was that if something got in there or the breather itself failed the plastic pieces would do less damage rather than having metal pieces wipe out the the whole cam chest.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
In actual fact where two parts rub together, such as here, the harder part tends to be the one that wears, as hard particles stick in the soft part, acting as an abrasive. Take plain bearing crankshafts for example, the crankshaft journals wear, despite having soft metal bearing shells.
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,091
Likes: 7,612
From: Poolville
If it's all that much of an issue, get rid of the rotating breather gear and install the S-S reed valve... Problem solved....
Update:... I actually like the idea of the reed valve..... Maybe that's why they went to it in the twinkles....
Update:... I actually like the idea of the reed valve..... Maybe that's why they went to it in the twinkles....
Last edited by 98hotrodfatboy; Jan 7, 2019 at 10:25 AM.
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