O-rings on drain plugs
- Thread starter WEM
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Simply because O-rings was invented in 1936 and became common during WWW2. As copper gaskets works reasonably well and properly used don't leak, Norton never found any reason for change. As British motorcycles was usually leaking oil anyhow, a small possible improvement on the drain plugs was unnecessary. The Japanese horizontally split wet sump crankcases where oil had a better chance of staying inside the crankcase made an drain plug oil leak more noticeable.
marshg246
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Besides what others have said, the recess in the Norton slider for the drain makes it very thin there. Only about 2-3 threads. Triumphs and BSAs are much thicker. If you were going to use an o-ring thick enough to seal, you might need a slightly longer screw and you might need to get it a little tighter than the copper washer which could strip the threads. So, I wouldn't do it on a Norton.
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Thats exactly what I do on my sump drain plug and others.
SUMP DRAIN
Use 3/32 x 1-1/8 ID O ring for sump plug with aluminum spacer that goes around the o ring and is about .010” shorter than oring. This way you can tighten down without damaging the Oring (use viton).
Fork drains with outer brass spacers to prevent crushing the Orings. Make a brass washer with .4” OD x .312” Id x .050’ thick. Install an Oring with 3/16” ID x 5/16 OD x 1/16” thick.
To prevent leaks at the fork damper bottom bolts. Open the ID of the fiber washer that locates at the bottom of the damper tube to .655″ Place a 5/8” OD x ½” ID x 1/16” Oring on the bottom of the damper tube. Install the fiber washer in the slider to avoid crushing the Oring.
Another option is a Nylon sump drain washer (I haven't tried one - anyone have any reliability feedback?)
SUMP DRAIN
Use 3/32 x 1-1/8 ID O ring for sump plug with aluminum spacer that goes around the o ring and is about .010” shorter than oring. This way you can tighten down without damaging the Oring (use viton).
Fork drains with outer brass spacers to prevent crushing the Orings. Make a brass washer with .4” OD x .312” Id x .050’ thick. Install an Oring with 3/16” ID x 5/16 OD x 1/16” thick.
To prevent leaks at the fork damper bottom bolts. Open the ID of the fiber washer that locates at the bottom of the damper tube to .655″ Place a 5/8” OD x ½” ID x 1/16” Oring on the bottom of the damper tube. Install the fiber washer in the slider to avoid crushing the Oring.
Another option is a Nylon sump drain washer (I haven't tried one - anyone have any reliability feedback?)
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concours
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Loctite 518 on the crush washer surfaces.
NO drips ever. So simple.
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Using nylon sump washer -same one- for 10 years. Works wellThats exactly what I do on my sump drain plug and others.
SUMP DRAIN
Use 3/32 x 1-1/8 ID O ring for sump plug with aluminum spacer that goes around the o ring and is about .010” shorter than oring. This way you can tighten down without damaging the Oring (use viton).
Fork drains with outer brass spacers to prevent crushing the Orings. Make a brass washer with .4” OD x .312” Id x .050’ thick. Install an Oring with 3/16” ID x 5/16 OD x 1/16” thick.
To prevent leaks at the fork damper bottom bolts. Open the ID of the fiber washer that locates at the bottom of the damper tube to .655″ Place a 5/8” OD x ½” ID x 1/16” Oring on the bottom of the damper tube. Install the fiber washer in the slider to avoid crushing the Oring.
Another option is a Nylon sump drain washer (I haven't tried one - anyone have any reliability feedback?)
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I usually think of a Dowty seal as a single use item. Particularly when I am using them on fuel taps.
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On modern fuel ask for Viton. I've reused them many times hardly a failure. The only one that springs to mind was the rubber insert fell out. Never ever had a leak.
concours
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Mis-application.
Use Loctite 567 sealant on the PIPE THREADS for fuel taps.
I use aluminum washers for the drain plugs.
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Misapplication? Tell that to the Triumph and Norton factories.
A dowty style washer was standard issue for the gas taps.
Here is the original style: https://www.baxtercycle.com/product/70-7351b/
Or you could use a more modern style:
www.mapcycle.com
Same difference. It is actually brilliant engineering, as it seals on three faces, including the threads. And will let you tweak the angle of the petcock without leaking.
Thread sealant is a better example of misapplication!!
It's main purpose is thread lubrication on large diameter coarse thread tapered pipe joints.
"LOCTITE® 567™ High Temperature Thread Sealant with PTFE is a general purpose instant thread sealant for taper/taper threads and fittings."
A dowty style washer was standard issue for the gas taps.
Here is the original style: https://www.baxtercycle.com/product/70-7351b/
Or you could use a more modern style:
Triumph, Norton, BSA, Petcock and Tachometer Housing Bonded O-Ring Washer
Sealing washer for tachometer and petcocks on Triumph, BSA and Norton models
www.mapcycle.com
Thread sealant is a better example of misapplication!!
It's main purpose is thread lubrication on large diameter coarse thread tapered pipe joints.
"LOCTITE® 567™ High Temperature Thread Sealant with PTFE is a general purpose instant thread sealant for taper/taper threads and fittings."
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I have then on the float bowl drain plugs, and remove them regularly to drain off the fuel to avoid "varnish" .... i have refitted the current ones 6 times without any leaks
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