1959 breather gear

[Plain]

New guy here. Hoping to find a gearhead or wrench to supply information concerning a 1959 FLH breather gear.
Can someone tell me what the o.d. of the stock FLH breather gear tube is? And, what is the diameter (i.d.) of the stock breather gear bore in the case? Where fitment is concerned, what is the usual wear limit before going to the 0.030" over aftermarket breather gear.
I apologize if this question has been asked and answered before. Humor me, I am old. I searched the forum as far as I could but did not find the issue addressed. I have searched every piece of documentation that I possess but cannot come up with the hard numbers. If this information resides somewhere that I have not discovered, and you can point me in that direction I would be greatful.

Thanks-----Plain

[Jack_Hester]

Plain -

I want to answer. I have a brand new breather valve in my shop. I have been unable to make the pilgrimage out there to measure it. The wife is gone to town, so I don't dare venture out there for now. I can get you the O.D. easy enough. I just closed up the last Big Twin gearcase that I had open. And, it is a brand new S&S set of cases. The breather valve fit very smooth. I'll see if I can find you some written specs on the fitment. But, it will have to be when I get out to the shop. Maybe this afternoon.

Jack

[Plain]

Jack: Would appreciate it very much if you could mic the breather.
For anyone's information, I burrowed down into the S&S site and found a sharp tech. This from S&S's Steve Welte:

"The breather gear is to be fitted at .0015 to .003. Service limit is at ..004. you can mike the breather you have and then mike the bore of the case to determine the limit your case is at. If you go to the .030 mike the outside of the breather and have the case bore done to allow .0015 running clearance."

Adios-----Plain

[Jack_Hester]

Plain -

The breather I have measures: 1.1232" O.D.. I'm figuring the nominal value is 1.1230" for factory spec..
Looks like you'll want a bore of 1.1245", for the close fit, and 1.1260" for the max bore, going by your specs from S&S.

Jack

[Plain]

Jack:

What is the brand of the breather valve that you are measuring? The breather valve that I just pulled out of the recently torn down 1959 FLH looks to be an OEM Harley valve. On the valve I measure 1.1240" at the gear end, and 1.1238" at the far end. Case bore mics 1.1261" at the gear end and 1.1263" at the far end. Depending on which measurement is used, I have a running clearance on the existing of from 0.0021" to 0.0025". The measurement on my valve is close enough to yours for me to feel that I am not possibly dealing with an oversized valve. History of previous work done on this engine is pretty well non existant.
When going back together it was my intention to replace the OEM breather valve with an S&S breather valve. However, if the S&S valve is in the 1.232" od range I am going to lose ground. May end up with the old trick of removing the screen clip, rotating the screen, spot welding it in and enlarging the holes to get the best breathing that I can out of the OEM valve.

Thanks for your help!

Adios-----Plain

[Jack_Hester]

Plain -

My breather valve is made by Eastern MC Parts. I would say that if your case bore is clean, with no scars, and the breather valve is likewise, you have a very safe, usable breather. Do check the thrust with it washed and the spacer in place. Do you have a manual to show you the method and specs on the thrust? If not, let me know and I will get them for you.

Jack

[Plain]

Jack:

Case bore is clean and breather valve likewise. Since I have .0025" clearance with it I will stay with it. Will remove the clip, rotate the screen and enlarge the holes. I have a full compliment of washers and always try to set one for minimum end play. Breather hole in case is the original cast eliptical hole, so it will get ground out to a correctly timed rectangular hole. Thanks for your help.

Adios-----Plain

[Plain]

Hello Jack: Me Again

I don't want to whip a dead mule, or belabor this subject, but I have a little more information before I give it up.

After viewing your post indicating that your breather measured 1.1232" and that you figured factory spec. was probably 1.1230" I figured that in my dotage I could no longer measure or that some nefarious degenerate had bungled my micrometer and it was no longer reading correctly. I put the micrometer on a standard, and no problem with the mic. Remeasured my gear and it is in truth 1.1240". Tracked down a friend that had a new S&S standard gear still in the plastic. The S&S gear mics at 1.1230", exactly as you predicted. My 1.1240" must be some aardvark manufacture.

Lurking on this forum I ran across a thread that indicated that you had been seriously busted up. Damn sorry to hear that and hope that you are mending well. And I doubly appreciate that you measured the gear to give me the information. Heal well Jack.

Adios-----Plain

[Jack_Hester]

Plain -

I am doing much better. The cane affords me freedom of movement that the walker did not. But, it's giving the mending ribs a serious workout. I don't care. I'm walking. I was out in the shop this morning. And, my wife and I just got back from a visit to my machinist buddy, Pat, to get some work done. My wife likes to go along, because this guy is into herbal medicine. The wife does cooking with herbs for seasoning and medicinal uses, as she has chronic back problems. My short visits to the shop are my walking and mental therepy.

Anyway, stick with your steel gear, if the clearance is to your liking. The plastics are an economics thing. Very bad for the engine. The plastics load up with any metal that goes through (and it does), and badly scars the bore of the breather chamber. Yours is slightly overbore from standard, then. That's good. And, belaboring is good, here. More info posted, means more info for all to have at their disposal. Forums like this are like encyclopedias that are ever growing. So, post it when you find out something new. Have a good one.

Jack

[Plain]

Jack:

Good to hear that you mending well. I may have confused you somewhat in my last post. I tend to do that.
The new S&S breather gear is not plastic. I ment that it was brand new, still in the plastic sack in the cardboard box. Never been opened so a really good candidate for obtaining an accurate measurement. The S&S gear is steel, very well made, and damn near a thing of beauty. Holes in the breather screen have been enlarged for better breathing. The oil evacuation hole has been enlongated to increase the duration of suction to the breather settling cavity. They have also changed the opening and closing specifications for maximum breather timing. According to the literature in the box, this was done primarily to facilitate oil scavenging in large displacement V2 style motor. "New specifications are harmless but not useful in most older engines." Shame that I can't use one in my engine. Fine looking well made breather gear.
Up the thread aways I mentioned that I was going to pop the clip, rotate the screen, and enlarge the holes in my current gear. Don't know when the last time was that you tried to remove or turn the screen in an old breather gear. Well Jack, there's hells own torment. I am going to be at this for a long time, or give it up. The odds of me obtaining another .001" over breather gear are slim to none. Lord knows when or where this one was acquired.
The cane may be rough on your ribs but really comes in handy to hook things and drag them over to you. Also does a fine job of thumping other people on the noggin when the situation requires. I will try to post information from time to time if Panhead doesn't run me off. See my post to him this date in the General section asking for redress.

Adios-----Plain

[Jack_Hester]

Plain -

My misunderstanding. You statement was perfectly clear. And, it is/was a good candidate for measuring to get some standard. I don't think that I've ever tried to remove one of these screens, with the intention of reusing. I'm satisfied that they are put in to be fail-proof, and maybe even people-proof.

Jack

[Plain]

Jack:

Thanks for cleaning that up. People proof sounds much better than the well deserved idiot proof!
Somewhere in my distant past I did that procedure on a breather gear. This one defies me. I have given it up as an exercise in futility, if not lunacy.

Adios-----Plain