Hello all, Just became the owner of a 85 K100rs. My gas cap locking mechanism has broken. I really dont want to get another locking gas cap. My Question is, is their a aftermarket gas cap that I can use as a replacement for the stock with some modification? Right now Im looking at the 4 bolt version of this But I'm not sure if it will work. Can anyone point me in a good direction? thanks

If you posted a link it didn't come through but I dont know of any caps. The very early K100s had a nonlocking cap but they would be very rare.

Welcome to the forum Roejen.

I've not heard of a straight replacement for the gas caps.

No doubt someone will chime in soon with more info.

Third time's a charm. Unfortunately we have few choices and if your cap's buggered you'll have to mend it or replace it. Motobins UK sell a repair kit which is basically the seals in the nose of the cap. The lock cylinder comes out fairly easy and can be re-keyed but if it's stuffed them you'll have to get a new one. The culprit is often corrosion down in the end of the lock.

The lock cylinder and tumbler itself is actually good. Its all the plastic stuff that Cracked and broke. I had to force the cap open to get into the tank. So the cap itself is fine. The tumbler still works...everything that attaches to the tumbler..not so much. I'm thinking of trying the Pro-tek 4 bolt gas tank cover like this one http://www.amazon.com/Pro-Tek-Keyless-Gas-Cap-Base/dp/B002OKN4GQ
Or perhaps taking something like this Bikers choice one and maybe modifying it or simple sealing it into place... Its a question of diameter I suppose. any suggestions, thoughts or Idea's? http://www.bikebandit.com/biker-s-choice-pop-up-gas-cap
Thanks for the response and I'm glad I'm here. This is my 1st motorcycle. I purchased it from someone who was unable to ride anymore for $250 after sitting in a garage for Almost 20 years. Odometer says 1100 miles on it. Guy hardly used it.

You have to be able to make a base attach to the aluminium of the tank and that base has to be able to seal. Neither of the two pictured are going to be the correct dimension. This is an ongoing, long-term issue, nothing else fits, and you will be better off finding a clean, second hand unit from another early K75, K100 or K1100. Mind that the bases are different in different countries due to fuel vapour release laws and also that with anything non-genuine you use, the small vent hole in the petrol cap's base must be left open, not covered up.

Here's a start:

http://shop.ebay.com.au/?_from=R40&_trksid=p3907.m570.l1313&_nkw=gas+cap+k100&_sacat=See-All-Categories

Congratulations on your rare find. It seems a shame that with that little mileage you wouldn't try to keep it original as possible. There are probably lots of folks on this forum that would love to be in that situation.

:| Yeah I saw the ones on Ebay already. Thanks for the suggestion though and more important, thanks for the info. Though not what I wanted to hear I atleast know now. Now I need to figure out why the right turn signal stays on and will not blink. The Left one will not turn on at all front or back. Thanks guys I really appreciate it.

If other lights are acting strangely like the indicators, check the starter motor for excess carbon dusting from the brushes. "What did he say?" Yes, it's true. There are several posts here about the subject. Of course, it could simply be the flasher relay.