214-636-7368
214-636-7368
Suggestions and opinions presented in "Tech Tips" are provided for the benefit of clubmembers and guests. If you're not completely comfortable with performing your own mechanicing please hire a qualified shop or independent mechanic. Bob Cox/Custom Classic Cycles
and the NTNOA are not responsible for accidents, property damage, injury or fatalities resulting from any information contained in "Tech Tips." • Unless otherwise stated, all graphics, photos, illustrations and copy in "Tech Tips" are the exclusive property of Bob Cox/Custom Classic Cycles • Copyright © 2018
This article covers seal replacement for a Norton Commando “Ceandess” brand fuel cap but may be applicable to other Ceandess caps with similar seal mounting. The original neoprene seal had a hard enough time keeping gas in when new much less after 40 + years. The problem... it's riveted in place.
The chrome on these flip-up caps holds up pretty well over the years but the spring loaded seal hardens and cracks. Often its metal disc holder and especially the rivet head that holds it in place rusts badly. In this case, the holder was okay so I replaced the seal with a modern polyurethane one, and the rusty rivet with a stainless bolt. After removing the cap from the tank, the first step is to carefully drill out the head of the retaining rivet. Use an oversize, sharp bit and the seal/holder will pop out once you’re through.
ou can now lay out the components. Don’t lose the small "rubber hose" spacer which goes on before the disc holder. If reusing the holder, Scotch brite and a dab of grease will help keep it from rusting. If it’s too far gone, new disc holders with integral neoprene seals are available from many British parts suppliers.
ow disassembled and cleaned, next tap the steel rivet that’s
still inside the mounting boss. You could drill it out and tap a much larger
retaining bolt but the rivet shank is thick-walled and once tapped accepts a
10 - 32 x 3/8” bolt perfectly. I use a button head allen bolt, flat washer and split washer all in stainless.
efore you start drilling make sure you have the correct drill bit
for the tap. In very, very small type on the tap is the
drill to use and they go by numbers not size. The 10-32 tap calls
for a #21 bit. Drill plenty deep but not too far for
obvious reasons. I first do a test tapping on a
piece of similar material.
s it worth saving or just buy a whole new gas
cap? If the chrome's decent I like to renew the original. It’s certainly much cheaper. Putting on
just the seal requires patience to seat it all the
way in the groove. A smear of grease helps. If your disc holder and rivet are in good order replace the seal only. In this case, the rivet
was rusted badly and had to go. With stainless fasteners
this will no longer happen. And you can unscrew it later.
Don’t forget this rubber spacer which goes on the mounting boss followed by the disc with seal.
The button head bolt and washers can be purchased online from a distributor such as albanycountyfasteners.com and are great for other motorcycle applications.
This seal is made
of ethanol fuel tolerant “proprietary” polyurethane.
Worth a try for $10. Neoprene ones are also available.
Not to scale
Test piece
Tap for #10-32 threads
#21 Tapping Bit
Commando “Ceandess”
Fuel Cap Seal Renewal  |