The key has been spinning in the lock of my tank cap since I got the bike and I had developed a little technique for opening it but it has been getting steadily worse. I decided I'd better do something about it before a Long trip this bank holiday weekend (St. Patrick's Day for those abroad. )

With the cap open I removed the 3 screws on the underside to get at the mechanism and removed the barrell. The 2 nibs on the bottom of the barrell had completely corroded away, the cause of most failures I suspect.

The receiver is plastic and you can see how the worn nibs had dameged the plastic...



I then had a bright idea as a temporoary fix...

drill two small holes where the sockets are....

(sorry for the poor focus)

url=https://servimg.com/view/16818459/81][/url]

put the lot back together and carry one of these for opening it...



Worked a treat and will keep me going until I can find a replacement at a reasonable cost.

88KE

88KE wrote:The key has been spinning in the lock of my tank cap since I got the bike and I had developed a little technique for opening it but it has been getting steadily worse. I decided I'd better do something about it before a Long trip this bank holiday weekend (St. Patrick's Day for those abroad. )

With the cap open I removed the 3 screws on the underside to get at the mechanism and removed the barrell. The 2 nibs on the bottom of the barrell had completely corroded away, the cause of most failures I suspect.

The receiver is plastic and you can see how the worn nibs had dameged the plastic...



I then had a bright idea as a temporoary fix...

drill two small holes where the sockets are....

(sorry for the poor focus)

url=https://servimg.com/view/16818459/81][/url]

put the lot back together and carry one of these for opening it...



Worked a treat and will keep me going until I can find a replacement at a reasonable cost.

88KE

I just replaced my whole cap and I have a spare one of these laying in the parts bucket.
If you want it give me a PM with your address.

Cheers, M

Oh no, not another thing to worry about on my new-to-me old bike! I know zero about locks. Tell me, would this corrosion still be a potential disaster on a long ride if I never lock the cap?

cool !!

brickrider wrote:Oh no, not another thing to worry about on my new-to-me old bike! I know zero about locks. Tell me, would this corrosion still be a potential disaster on a long ride if I never lock the cap?

From what poking around that I did with the lock et al - this could be a serious trip hic-cup.

The two pins at the bottom of the lock barrel engage into the plastic cup shown earlier in this thread. The plastic bit has a cam on the side that operates the opening mechanism.

If you lose those two pins to corrosion then the cap won't open.

The lock can only be changed/repaired with the cap open.

It would mean destroying the lock to open the tank (in the field) or you hope that the gas station is next door to a lock smith.

I had a problem with my cap in that someone had opened the cap to (I believe) fix the vent. They had misaligned the plastic cup with the lock and the bottom of the cup was chewed up.

There was also a perimeter crack around the valve due to the increased height of the assembly when re-assembled due to the pins not engaging.

Cheers, M

Yep Moto smith has got it right. You can only do this repair with the tank cap open. There have been posts in other threads about drilling out the lock in which case the cap referred to above would keep debris out of the tank. However if the plastic is chewed, as with mine and motosmiths the I'm not sure what drilling the lock would do. If it allowed removal of the barrel then you could get the cap open with some sharp tool or other.

What prompted me to do this quick fix before total on the road failure was a couple of blood pressure raising sessions on forecourts with a spinning key.

BTW if your key is spinning try pulling the cap up with the finger tips of one hand whilst pushing down on and turning the key with your other hand.

88KE