K75 Gas Cap Dilemma

[Vankind]

Hello all, first post here.

While replacing fuel pump and filter on a “new to me” ‘87 K75s, the fuel cap assembly fell from the seat and separated upon impact. Nothing appears to be broken or missing, but I’ve made numerous attempts to reassemble with no success.
The cone-shaped plastic piece on bottom of lock cylinder is separated and I cannot figure out how it goes back together.
I’ve scoured the inter web and found some information, but no detailed explanation of how this piece is reattached.
As I didn’t remove the piece on my own, I don’t want to force anything and break it in the process. Any help would be greatly appreciated.

[frankenduck]

You need to take it apart:

https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/rekey/rekey.htm#gascap

[Vankind]

Thanks for the link, very helpful.
I’ve disassembled & reassembled multiple times, but without removing the lock, I’ll give this a try.

[The Mighty Gryphon]

Have you seen this video?

[Vankind]

Yes, thanks.
After watching repeatedly, I only now realized the collar on mine did in fact break off inside vent cap.
The break is so clean, I couldn’t see it, nor was I looking for it.
I’ll attempt to plastic weld for now and see how long it holds before needing replacement.

[frankenduck]

If the plastic weld breaks with the gas gap closed then you will not be able open the gas cap. 
 It'll probably break at a gas station when you pull in to gas up. I'd replace the broken part.

JMHO

[Vankind]

Very good point, I thought about the longevity of plastic weld under constant exposure to fumes.
 I’ll look for a used parts cap in the interim.

Thank you.

[Laitch]

Here's a thread that might be relevant until Vankind repairs or replaces the fuel cap.