harleyKmodel

Hey all, another question while sorting my 54KH primary chain/clutch area. The crank case oil syphon tube 25101-53A threads into the fitting 25111-53 it also shows 25350-37 as a breather valve complete in between the syphon tube and fitting. What does this little valve look like? I'll see if it is in some of the boxes I have.

I'll also need to know what position it is installed in. I remember a while back I read something on this but I can't seem to re-find it.

Also is the tube I have correct? I think back in the day I might have removed one from a 52 Pan I converted to belt drive and might have migrated to my K part mess.

Terry

Terry,

Check out this article - with a picture from the factory showing where it goes.

The 25530-37 is a little disk which fits inside the hollow 25111-53 bolt. It's about 1/8" thick. If I remember correctly, it's rubber-like with a metal disk encased in it. There should be a copper/brass washer that goes with it. It's a one-way valve which uses engine vacuum to suck excess oil out of the chain case and back into the crankcase. One side has a small hole and the other side has a large hole, but I can't remember which is which. You're going to have to suck it to find out which way it goes.

The 52-53 Ks had all kinds of chain case breathing and filling up with oil problems. Sometime during 1953 the factory came up with the syphon tube idea. The first mention of it is in the 1954 Spare Parts Catalog, and it shows the -53A tube. There probably was a very short-lived -53 part, but I don't think anyone knows the difference.



At 55 KH 1300, the factory drilled a hole near the bottom of the chain case and into the crankcase. They used a different one-way valve, the 25075-55, and abandoned the syphon tube. The 1956 Spare Parts Catalog shows both.

Terry, a few pictures of what the 25350-37 breather valve looks like. I took apart a complete crankcase oil syphon tube and popped the valve out. No evidence of any brass or copper washer. Pictures show direction of flow.
Stan

Thanks guys, I'll have to search for that crazy little check valve. This was a great help. Knowing what I am looking for helps a ton. Most hardware and fittings are in labeled bags but there are some things mixed about. I just don't recognize the valve but now I know what to look for.


Terry

hd54kh wrote:Thanks guys, I'll have to search for that crazy little check valve. This was a great help. Knowing what I am looking for helps a ton. Most hardware and fittings are in labeled bags but there are some things mixed about. I just don't recognize the valve but now I know what to look for.

When you get tired of looking through all those bags, you can order a 25350-37 valve from Enfield Racing. It's $25, so you might not want to give up the hunt too early.

Download their catalog from the website - lots of good stuff. KR valves? Yup. KH Tappet Screws? Yup, they've got them too.

Dave

Thank you Stan and Dave, found it in the first box, got to get out and play the lottery today. It was in a bag of the unknown parts.

This was a great help as you guys had the exact info I needed to know what to look for.

Terry

I can tell you guys one thing if that valve is in backwards you spit oil out the breather on the primary. It took me a little bit of research and a while to figure this out.