yes, yet another stuck fuel cap

[tobster57]

Hiya, I've just bought a 1986 R65 which has been sitting unused for over 10 years. I need to check the condition of the interior of the fuel tank but unfortunately it seems that the last owner left the fuel cap locked and i cannot get it to unlock. Despite my best efforts the key will not go into the lock more than a few mm. So, as the plastic cap (which has no BMW logo) just spins is my best way of getting the fuel cap off to do this hole drill trick described on the largaider site?
I have looked for someone else reporting this scenario of a locked cap but i have failed - apologies if this has been covered before. Help

[Kurt in S.A.]

Welcome! Snowbum has some suggestions for a stuck gas cap, about mid-way down this page:

https://bmwmotorcycletech.info/fuel-caps-airheads-K.htm

Kurt

[tobster57]

Thanks Kurt. I wasn’t sure whether having a closed lock made any difference to the method for removing the cap

[SteveD]

Welcommen!

...left the fuel cap locked and i cannot get it to unlock. Despite my best efforts the key will not go into the lock more than a few mm. So, as the plastic cap (which has no BMW logo) ...

Is it the oem cap? Pix?

[tobster57]

Yes, I think so. I’ve managed to remove the outer ring.

[Rob Frankham]

Don't know what you're 'best efforts' are but if you haven't done so, I would certainly try injecting a good releasing fluid or penetrating oil directly into the lock, then leave it for a week, possibly adding more fluid daily. It's worth trying to free the lock rather than risking destroying the cap. There are a couple of established ways of removing the cap if it's impossible to shift it...

1) take a rope and loop it through the handle then stand on the footpegs, wrap the rope around your shoulders and use the muscles of your back and legs to force the top of the cap... This allows the inner plug to be unscrewed. The benefits of this are that it allows access to the lock mechanism and you may be able to free it up. The cap can normally be reassembled.

2) Drill a hole and insert a screw as described by Largiader and others. This allows you to unscrew the cap and allows you to continue to use it but not lock it.

Rob

[tobster57]

Thanks Rob. I will keep on spraying penetrating oil into the lock. I have also tried the rope trick but nothing budged. I will try again & try to be braver.

[Rob Frankham]

Thanks Rob. I will keep on spraying penetrating oil into the lock. I have also tried the rope trick but nothing budged. I will try again & try to be braver.

I have used the 'rope trick' but only on one occasion and yes, it did work. On that occasion, I was able to clean up the locking mechanism and the cap was used and lockable for the rest of the life of the bike so it's worth the effort.

Rob

[SteveD]

Here's the cap deconstructed...it's press fitted together.
When refitting it, lining up those holes (if yours has them) and inserting a small self tapper will stop it from turning too, avoiding the screw from the top technique. The outer plastic ring covers it. Mine has been modded accordingly for over 20 years. Also, I never lock it.

[tobster57]

So I’m persevering with the rope trick as well as soaking the lock with plus gas penetrating fluid. I am pulling really hard but it’s not budging. Is the successful pulling action a gradual pull or a sharp tug?