S&S cases with stock steel breather valve

[Don D]

I don't know that for sure, a proper boring job to begin with would have been ready to use and on size. It appears the solution is a new S&S breather based on the dimensions provided.

[JW113]

I have a new S&S breather gear here, 33-4241 for L1977-99 BT. Gear end the barrel measures 1.1225, open end measures 1.1223 with properly calibrated Starrett 10ths mic.

That is interesting. Implies a very slight taper from gear to open end. Which, if my measurements of the bore are any way accurate, would probably work. The gear I have is completely cylindrical. I have an early style S&S breather gear in the mail, will see what happens with that before I touch the case.

One odd thing to note also, this breather gear I have has a tiny little hub on it (where the spacer sits on), like maybe 1/8th inch? The spacers have more like a 1/4" hole, so I had to make a centering sleeve for the spacer when both were in the stock cases. Ever heard of that? I don't know what the stock pre-77 breather gears look like, I assumed this was one. But maybe not?

-JW

[SP33DY]

The factory changed the pitch diameter of the breather gear, cam gear and pinion gear in the middle of the 1977 model year. Early and late parts shouldn't be mixed so it's important to know which series of parts you have.
I looked through my limited supply of factory bulletins from back then and found it. Service Bulletin M-743 from April 3, 1979 has the details. Unfortunately it only gives pitch diameters of cam and pinion gears, nothing about the breather measurement.
You need a pair of 0.105" gage pins to make your measurement across the gears. The difference is enough to identify which series you have.

1954 to early  '77
Pinion gears range from 1.4440" to 1.4490"
Cam gears range from 2.7665" to 2.7715"

Late 1977 up
Pinion gears range from 1.4710" to 1.4756"
Cam gears range from 2.7324" to 2.7394"

[JW113]

Yeah, I knew about the gear teeth change in late '77. That's why I pressed my original cam gear onto the new Andrews #2, and am keeping the stock pinion, oil pump drive, and breather gears. Also, I believe the L-'77 and later stock HD cam gears have an annular groove in the side, the E'77 and earlier do not.

But what about this:

You cannot see attachments on this board.

See how this breather gear has a tiny little nib on it (3/16") to center the steel end play spacer, yet any spacer that I have ever seen has a larger (5/16") hole in it. You can see how I had to make a centering sleeve (out of a piece of rubber tubing) for the spacer in the lower right. WTF is with that? Are ALL early style breather gears like this? And did they make "special" spacers for the pre-77 breather gears? Guess I'll go dig around in the parts book, but I sure ain't ever seen anything but steel, or plastic. Not steel with a small hole...

-JW

[Ohio HD]

You need shims for 1970 to early 1979, for the small nub on the breather gear. Late 1979 and up were larger.


25314-50   0.120   '70 to E'79
25315-50   0.125   '70 to E'79
25316-52   0.110   '70 to E'79
25313-50   0.115   '70 to E'79

[JW113]

Got it, thanks Ohio! Since I'm going to try the S&S breather gear, hopefully it uses the later style. Guess I'll find out soon enough.

-JW

[Ohio HD]

I was wondering that too, what part number breather did you order?

[JW113]

S&S 33-4246 for 48-77 Big Twin.

-JW

[Ohio HD]

I would think that one will use the smaller ID shims.

[billbuilds]

    Early and late Shovelhead breather gears are easy to identify since the early ones have a flat face and the late ones have the recess milled into them. Both of the gears in the first picture are aftermarket. The second pic is a stock early one with spacer. (I mean shim).

[JW113]

Cool, this is good info. It appears these two aftermarket gears use the late style spacer with 5/16" hole. The gear faces follow the same marking as the cam gears, i.e. old = flat, new = annular groove. Will see what this early style S&S ends up, either way (small hole spacer or large hole), I have my little rubber centering sleeve to use the late style, regardless.

-JW

[JW113]

Well. Well, well, well, well. All's well that end's well. Right?
 

My new S&S breather gear came today. It dropped right in like a round peg in a round hole. I measured it, near the gear is 1.1230, near the hole at the other end 1.1220. PLENTY of clearance. The S&S tech was correct, get the S&S breather gear. Would have been real nice of them to put that in the notes for the cases, but oh well. Problem-o solved-o.

Thanks for all the feedback and comments. Learned something new. Again.
 

-JW

[Ohio HD]

Good news, but strange.

There must be some answer, I mean they sell that breather for stock replacement. 

[JW113]

Well, all I can do is chalk it up to "it's from the AMF years". Who the <cuss> knows what came out of the factory in that period, and how well dimensions and quality were controlled. AMF Harley-Davidsons had a bit of a bad rep, now and even back in the day. I think quality was all over the map, Monday or Friday bike, some OK, some not OK, that kind of thing. Typical situation when you ramp up production without making the corresponding investment into the factory infrastructure.

Anyway, tis on all of use AMF Shovelhead owners to "un-AMF" them. Once that is done, they're damn fine machines.

Oh, and the spacer nib on the S&S Gear...  the big one (5/16"), uses late style spacers. Yay! That's all I have!

-JW

[Buglet]

  It amazes me how many wanted to go in the hole without checking the real problem or want to blame the manufacturer.

[cheech]

All said and done and solved.
In all this though, are you 100% that it is indeed a OEM breather you took out of this 45 year old bike?

[JW113]

You kind of hit the nail on the head with "45 year old bike". After 45 years, who can be sure of anything that was done to it in the past? No, I have no idea if this is the breather gear that was in it when it rolled off the assembly line. It looks like OEM, but I have no idea who else makes breather valves for early Shovelheads (that one was definitely not S&S), or why anyone would have replaced it in the past. The breather bore in the stock case was pristine.

-JW

[cheech]

Hard to say, if it is or not OEM.
Who knows who all made them back then also.
Sifton?  LOL
Little story.
I know Sifton got bought out by Taiwan Tedd cycle.
So no comparison to the old days perhaps.
I inherited an Evo job where the guy claims the oil pump went out, he started the tear down, got in over his head, brought it to me.
He bought a Sifton oil pump kit, included the breather gear for whatever reason.
The breather was about as round as a football. 

[capn]

Only origial HD parts on my 76 are flywheels ,and cylinders. Rods are S&S.

[JW113]

I'm right there with ya, Capn. Wheels (not shafts), rods, cylinders, nose cone, rocker boxes (not the innards) are now the only original HD parts. Everything else is S&S, Jims, Andrews, KB, Cometic.

-JW