25287-37 - what's it do?

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25287-37 - what's it do?

Postby hennesse » Thu Jul 24, 2014 8:07 pm

Hi guys,

I have no idea what "25287-37 SPRING, breather seal" does. I need me some edumacation. Cen you hep?

The previous owner of my 1962 XLCH removed the generator and installed a blank-off plate for racing. I see in the parts book that there is a spring (#21 in the illustration) that goes inside the bushing (#19) in the gear case cover. I don't understand what this spring does. There's no "breather seal" that I can see that the "spring, breather seal" would spring. I don't envision this spring keeping much oil out of the breather by itself.

So what's it for? And if I really need one, does anyone have a spare?

Dave
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Re: 25287-37 - what's it do?

Postby EKHKHK56 » Fri Jul 25, 2014 3:25 am

Hello, the 25265-52 bushing rides in the cam cover spring loaded and allows crankcase pressure to vent out the tube. This breather floats spring loaded in the cover. This style was used 52-62. To the best of my knowledge! Have to look to see if I have one. Erik
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Re: 25287-37 - what's it do?

Postby 55khkjoe » Fri Jul 25, 2014 8:01 am

Hi dave, the spring kept pressure on the bushing that rests on the generator oil slinger gear on end of generator. not much oil gets up there. my 53KK was no generator and block off plate and I never had any oil come out of the breather tube.Joe
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Re: 25287-37 - what's it do?

Postby 1955KH » Fri Jul 25, 2014 7:46 pm

Hello Dave,
Parts books do not show the fine points, in this case that the Oil Separator Bush is a 2-part item, the inner flanged brass bit is held into the outer bush by two tabs bent into slots in the outer but allowing it to slide. The spring sits on the other 4 tabs and presses the flange against the drilled generator drive gear, and with negative crankcase pressure stops any flow in the breather tube. With positive pressure the flanged bush lifts off and venting takes place.
Thousands of miles away in New Zealand with no one to ask all this was a mystery until I discovered Stan Diener in Ohio who was a life-saver on many occasions.
Later I managed to get both a new bush assembly and spring from http://www.tomsnosparts.com/ which is a great source. However I have just checked and they no longer have the bush unfortunately. The spring they do have, but not much use on its own.
Michael.
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Re: 25287-37 - what's it do?

Postby hennesse » Sat Jul 26, 2014 5:07 pm

1955KH wrote:Hello Dave,
Parts books do not show the fine points, in this case that the Oil Separator Bush is a 2-part item, the inner flanged brass bit is held into the outer bush by two tabs bent into slots in the outer but allowing it to slide. The spring sits on the other 4 tabs and presses the flange against the drilled generator drive gear, and with negative crankcase pressure stops any flow in the breather tube. With positive pressure the flanged bush lifts off and venting takes place.
Michael.


Michael,

You guys down there in the Antipodes really know your stuff! The piece you describe would certainly give the spring a reason for being. And the whole setup then makes sense! I just popped the generator off my 54 KH, and I now see how it looks. Duh, perhaps I should have done that before.

Here are the photos you sent me via email - maybe they'll help others. Also, I found the Seal ring, oil deflector is sold separately as 25270-52 http://www.nosparts.nl has them.

HOWEVER, this setup is designed for generator gears with the oil singer. My understanding is that 1958-1962 generators used a plain 13 tooth gear - no slinger. So the Seal ring would have nothing to ride against. One person told me that the seal ring and spring were just not used on these years. I'm starting to suspect this might be the case, although it leaves the breather area wide open.

My understanding is that in 1963, the gear case cover changed, and the generator used a plain 14 tooth gear with a large washer - and a different "Deflector, oil separator". The large washer would give a place for the spring loaded seal ring to ride against. I can't see (from the parts book) that any of the gears changed in 63 except the generator gear and washer, so maybe the generator area is the only difference between the 57-62 and 63-up gear case covers. ???

This just keeps getting murkier and murkier!
Dave

P.S. Does anyone have a parts book from the 1958 to 1962 era? It would be interesting to see the gearcase and generator sections.
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25270-52.jpg
Here's the seal ring 25270-52
25270-52.jpg (9.1 KiB) Viewed 21751 times
Bush-2X.jpg
Michael's photo of 25265-52
Bush-2X.jpg (63.78 KiB) Viewed 21751 times
Bush-1X.jpg
Michael's photo of 25265-52
Bush-1X.jpg (39.12 KiB) Viewed 21751 times
25265-63.jpg
The 1963 Deflector, oil separator 25265-63
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Re: 25287-37 - what's it do?

Postby dr dick » Sun Jul 27, 2014 8:34 pm

from 52-e84 there were 3 gen drive gears
all 14t (13t is big twin)

31071-52 or -52a used 52-57 (the model 52 generator)
this gear is retained to armature by cross pin
mates to spring loaded cam cover

31071-58 used 58-62. (mod 58 & 61 gens)
no cross pin hole.
mates to spring loaded cam cover

31071-63 used 63-e84 (mod 61, 65, 65a, & hitatchi)
this is a bare gear. no oil slinger. uses the fender washer instead.
mates to cam cover with the pressed in alum tophat.
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Re: 25287-37 - what's it do?

Postby hennesse » Tue Jul 29, 2014 1:09 pm

Thanks Dr. Dick.

I've found that almost all the sellers on eBay and other places (including otherwise reliable sellers) horribly misrepresent the part numbers and fitment of generator gears. This had me really confused. I'm sure it has confused others too. I think I've got it worked out now.

Please take a look at this page http://www.harleykmodel.com/technical/generators/index.html and make sure I've now got it correctly.

Dave
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Re: 25287-37 - what's it do?

Postby dr dick » Tue Jul 29, 2014 6:09 pm

thats pretty darned concise.
i dont know the difference between the -52 and the -52a gear.

i seem to remember the a length difference (dim d) between the -63 and the -63a. with the -63a being longer to decrease air gap between washer and tophat.
there may have been a .0005" diameter reduction of the cylindrical bore of the 63a too.
this needs to be verified as my memory aint what it used to be.

be careful of the 45" gears.
the 57< wl/g three brush gears these look like the -52's but the od of the slinger is smaller.
same goes for two brush wl/g gears used with the mod 58 and 64. smaller slinger than the -58 gear.

also when the -65a gen came along so did the vinyl covered, bolt tensioned, brush band.
i believe the -65 gen still used the steel and spring band.
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