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fork cap breather valve.

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chuck58pan
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fork cap breather valve.

#1

Post by chuck58pan » Mon Dec 29, 2008 3:17 am

Hello, should it be possible to blow air through fork tube cap breather ,one or both directions (in/out

or both ways ? Or is my feeble air-supply insufficient to check it. Thanks Chuck



VT

Re: fork cap breather valve.

#2

Post by VT » Mon Dec 29, 2008 3:27 am

No you shouldn't be able to. There is a separate part number for the packing material 45757-49 (breather valve complete). It may be compress steel wool type material in them now. The bottom of some (45754-49) bracket bolts are crimped to reflect something being installed inside them. I guess the only way to know is to take one apart.

chuck58pan
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Re: fork cap breather valve.

#3

Post by chuck58pan » Mon Dec 29, 2008 4:22 am

VT, thanks for the info. never did see anything about packing but it mekes good sense to separate the wheat from the chaff. I will get the parts and intall on some spares . for now i guess my caps are ok. thanks Chuck

VT

Re: fork cap breather valve.

#4

Post by VT » Mon Dec 29, 2008 4:35 am

I over-compressed a set of Glide forks once riding it up the ramp and into a trailer. Hydrl. fluid came out of that side vent hole in both of the bracket bolts. So, the breather valve was doing it's job. The bracket bolts need those baffle-discs sticks screwed into the bottom too. The V-Twin fork kits don't ship with them.

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Re: fork cap breather valve.

#5

Post by fourthgear » Tue Dec 30, 2008 12:55 am

There is a photo some where in this sight of a disassembled cap ,no valve in there , at least the std. cap , not sure of the adj. type .. It is nothing more than a metering device or oriface system .Air is discharged through the oriface at a metered rate and returned the same way .( good reason to change that fluid in there on a reg. maintenace schedule )

Try looking up Hydraglide front ends in the knowledge base or past threads .

mbskeam
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Re: fork cap breather valve.

#6

Post by mbskeam » Tue Dec 30, 2008 1:16 am

I think that air should go thru these,
the stack of baffles is just that, it separates the oil out from the air, so that it does not blow out the breather hole, if this hole is plugged, my guess is the traped air is going to go someplace when compressed, like out the slider seals....

mbskeam

chuck58pan
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Re: fork cap breather valve.

#7

Post by chuck58pan » Tue Dec 30, 2008 4:11 am

Thanks for the insights. I read that the breather is staked in three positions and if it can,t be unstaked you may drill the whole and hopfully twist or lever it out. i like getting into things because although it requires finding and acquiring parts, almost without fail when i start checking things I find some condition that i would prefer brought-up to a more sanitery state. In this particular case the fluid in the forks was of a brownish tint so i am assuming that same broken down hydraulic fluid has left the inside of the cap with some degree of rust. Thanks again,
chuck

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Re: fork cap breather valve.

#8

Post by hydra74 » Tue Dec 30, 2008 5:03 pm

Here is the Photo, its an repro cap i think

the air is going in and out
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VT

Re: fork cap breather valve.

#9

Post by VT » Tue Dec 30, 2008 5:11 pm

Hey! Is that "Magic Wadding" chrome cleaner wool or what :?:
You might could get some close-ups of that little aspirator valve. Was the wool on top on the valve or below or was the valve wrapped in wool? Or, is that part on the right which I just called a valve actually just a threaded plug end for the "baffle stick" ? I don't see any threads in the (valve) hole. There needs to be for the baffle stick to screw into. Without the baffle stick installed, you'll get a solid stream of hydraulic fluid squirting out the bracket bolt side-vent hole. Well, I guess the wool would eliminate a solid stream and just create a pressurized ooze.
Thanks for sacrificing the bracket bolt so we all can learn something.

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Re: fork cap breather valve.

#10

Post by Panacea » Wed Dec 31, 2008 12:57 am

VT, I don't have the baffles installed in my fork, and I don't get any oil squirting out anywhere....Mike

fourthgear
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Re: fork cap breather valve.

#11

Post by fourthgear » Wed Dec 31, 2008 1:50 am

I believe my baffles are held in place by the fork tube nut ( not sure as exact name , but its the one that compresses the spring )and the breather bolt screws into it. Damn , I knew I should keep a manual in my back pocket !

Thanks, hydra74 , Thats the photo I remember.

VT

Re: fork cap breather valve.

#12

Post by VT » Wed Dec 31, 2008 2:26 am

I don't have the baffles installed in my fork, and I don't get any oil squirting out anywhere....Mike
Must be why V-Twin's forks don't ship with them. Their Glide forks were trimmed of parts to the bare essentials and the later style (Gary Bang sold) slider seals. The sliders themselves are made in Mexico. Hand polished. Easily scratched, but nice to have. Except for a .020 to 0.30" slider floor level discrepancy, V-Twin produces a good product.
Let me say this about my V-Twin, as shipped fork tube plugs. They shipped with no baffle sticks (baffle discs on a shaft with a nut on the threaded end to lock to the bottom of the fork tube plug (you're right hydra74, I got hung up on the hex bolt). Anyway there's a 1/4" or 5/16 hole in the tube plug. Goes all the way through. There's a bleed hole in the plug, that vents the air that the baffles separate from foam. What's to keep fluid from bypassing the bleed hole and going through the easier 1/4" hole?
I dunno.... we need some pics and diagrams of the plug and the inner bleed-thru hole and the baffle and a schematic of how the air and fluid is moved around in a complete fork compression cycle.
If we don't re-invent and record some of this lost information no body will.
Of note: The Harley-Davidson Motor Co.® ordered both volumes of our books in mid-December. We sent them directly to Dept. X.
They either ordered the books because someone has a Panhead that they're working on, doubtful if ordered just for a "read", but they didn't order the books to sue Stett or myself, or to issue a cease and desist after reading them. Maybe they still want to be in the old Harley parts business. They have this site as a direct link to their Harley-Davidson® Panhead past. When anyone at Harley-Davidson® clicks http://hydra-glide.com/ it opens to the home page and the Harley-Davidson® logo. We are the caretakers.
I feel that 2009 will be a good year for motorcycles and a good year for Panheads.

neilw
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Re: fork cap breather valve.

#13

Post by neilw » Wed Dec 31, 2008 7:11 am

on these fork caps with breather valves in them,I found the best way to check them was to put a little drop of oil on my finger and dab a bit over the tiny breather hole in the cap then I compress the fork and let it go if the oil gets blown out there working ok .If they leak while riding they need repacing. They didn't use these in 49 ,the first year of hydra glide forks and probably blew seals .These are nothing to do with baffles that are inside the fork tube ,as you mentioned they are just in the top cap.( someone answered andIthought maybe they were referingto the baffles).They don't come fromthe factory with steel wool in them. ayear ago I made a study on these and no one from any forum or at antique cycle or the HD dealers new how to check em .Thing is they are mostly young guys now and are mostly working newer bikes ,newer to me is 1980 and up. Here in Calgary they had a pair in stock for about $20.00 each as I recall ,and since I couldnt find out how to check them I got creative and started wondering why they were there ,since they are called breather valve they had to breath I figured .I have 4 caps and 3 work ok 1 doesnt.
I can send photosfrom one of my parts books if you tell me how to do it .
All they have is 2 parts to them ,the washer that has the 3 little tabs you bend over to lock them in place and the little valve .
Oh yeah in my research I tried blowing compressed air through them but I couldnt tel anything by that ,at the same time I tried blowing throug them but couldn't blow hard enough ,it wasn't till I but them back in the fork tube and compressedthem that I could see the oil dissapearing.
Good luck..
Neil
PS my bad spelling and running words together is because I cant delete anything ,I have to erase everything so I just said screw it ,and guessed yous would figure out what I'm saying .I'm born here and talk english/Canadian Aye!

neilw
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Re: fork cap breather valve.

#14

Post by neilw » Wed Dec 31, 2008 8:50 am

My apologies for the wrong info regarding the "tabs on the washer you bend over on the fork cap breather" I just mentioned .I got thinking more about this and never did take one apart but started to about a year and a half ago ,and when I found I had 3 good ones I stopped..This isn't a washer it is much thicker by far ( as I'm sure you noticed because your looking at yours).I have it in my hand here and I see I have bent the stakes back ,I dont even see them now.I'm wondering if they are part of the cap wall .It apears they are .It's -20F up here and I dont have a big enough furnace in my garage to heat it unless it above -10 or so ,otherwise I'd have it apart by now. I did pry the stakes back but couldn't get the "Oil Seal ,tube plug" part 45733-48 " .Harley says they used them from 49 to early 47.And since I'm getting into this I might as well add what Bruce Palmer says in his "How to restore your harley " book (page 51) "the early 1949 glide fork did not have vented tube caps.By mid 1949,the glide fork had a vented cap with a grease fitting in it for oiling.This fitting was covered by a domed cap.By late 1949,this was replaced by the standard,vented cap" .
If it gets warmer I'm going to take this one apart ,maybe drill it out ,or if you get yours apart first I'd really like to know exactly whats in them. If you find the oil test I described shows your are ok ,then when It warms up I will take this one apart and let you know whats in them..
Neil

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Re: fork cap breather valve.

#15

Post by hydra74 » Wed Dec 31, 2008 4:52 pm

here,s a scan from my parts book the breather valve is used in the early-49 and late caps (45757-49

the wool in the cap i opened let the air in the fork in and out proberly its aftermarket
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