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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Vankind on April 21, 2025, 05:22:03 PM

Title: K75 Gas Cap Dilemma
Post by: Vankind on April 21, 2025, 05:22:03 PM
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.
Title: Re: K75 Gas Cap Dilemma
Post by: frankenduck on April 21, 2025, 06:11:38 PM
You need to take it apart:

https://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/rekey/rekey.htm#gascap
Title: Re: K75 Gas Cap Dilemma
Post by: Vankind on April 21, 2025, 08:34:30 PM
Thanks for the link, very helpful.
I’ve disassembled & reassembled multiple times, but without removing the lock, I’ll give this a try.
Title: Re: K75 Gas Cap Dilemma
Post by: The Mighty Gryphon on April 21, 2025, 08:48:21 PM
Have you seen this video?

https://www.youtube.com/watch?v=Mwpt9IumBCc
Title: Re: K75 Gas Cap Dilemma
Post by: Vankind on April 21, 2025, 10:11:29 PM
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.


Title: Re: K75 Gas Cap Dilemma
Post by: frankenduck on April 21, 2025, 11:28:15 PM
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
Title: Re: K75 Gas Cap Dilemma
Post by: Vankind on April 21, 2025, 11:54:31 PM
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.
Title: Re: K75 Gas Cap Dilemma
Post by: Laitch on April 29, 2025, 10:34:59 AM
Here's a thread that might be relevant (https://www.k100-forum.com/t9469-open-a-petrol-tank-cap-which-has-a-broken-lock) until Vankind repairs or replaces the fuel cap.