Oil Tank Cap Seal

Needing to replace the seal under the oil filler cap. Any tricks to fettle it out, new one in without damaging stuff?

Confession: asking for my Velocette's oil cap, but they are of similar design to commando, without dip stick. In fact, commando cap fits velo tank nicely and dip H/L marks sit right in middle between the upper/lower lines on the tank's external level sticker(velos have no dipstick and advice is to use your finger into tank...if you dip into oil level is good!).

The velo guys don't seem to know these seals are replaceable for some reason.

Same for Triumph and Norton. Cork. Part 82-4047, AN has them. Rip the old out, put the cork seal in position and push it past the two indents in the cap and it's in place. When new, they sometimes make it hard to get the cap on the first time or two but them form into place.

I use the one sold by JS motorsport. Does the trick.

marshg246 said:

Same for Triumph and Norton. Cork. Part 82-4047, AN has them. Rip the old out, put the cork seal in position and push it past the two indents in the cap and it's in place. When new, they sometimes make it hard to get the cap on the first time or two but them form into place.

Click to expand...

Velo's seal does seem to be jammed underneath the inner cone shaped section, so I'd think it might be difficult to stuff a new one in the same way. The cone shaped piece has what looks like a cotter pin looped end sticking out at the vertex...was thinking maybe some sort of trick to release the inner from outer parts to renew seal, change spring etc. Velo guys state the loop bit is to affix a tether chain to stop cap loss.
Commando on left,Velo on right:

Tornado said:

The cone shaped piece has what looks like a cotter pin looped end sticking out at the vertex...was thinking maybe some sort of trick to release the inner from outer parts to renew seal, change spring etc.

Click to expand...

I'd think it was more likely intended for attaching a chain with a wire clip.

If I do replace the velo cap, I would most likely get a commando type with dipstick. But my commando cap is a dull metal finish, ones on AN and other sites seem to be just zinc plated. Not important on commando as hidden under seat, but the velo cap is on full display at side of bike so got to look spiffy.

Worked for me.................
NORTON COMMANDO - OIL TANK CAP SEAL Part #: NORTON-2 Silicone seal

Tornado said:

If I do replace the velo cap, I would most likely get a commando type with dipstick. But my commando cap is a dull metal finish, ones on AN and other sites seem to be just zinc plated. Not important on commando as hidden under seat, but the velo cap is on full display at side of bike so got to look spiffy.

Click to expand...

Tornado,

My 1970 BSA 441 Victor and my 1970 BSA 650 Thunderbolt both use the Ceandess oil tank cap which has a dipstick and both are chrome plated. Compared to the Norton, my Thunderbolt dipstick is 1 1/4 inch longer and the Victor 1/2 inch longer.

Peter Firkins

I have found the cork gasket better than the rubber one.