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Fuel filler caps not seating correctly, How to cure it!?

Posted: Wed Aug 02, 2017 1:02 pm
by sportston
I've noticed a common problem on our 1970s GT Suzukis. The fuel filler caps on many of them do not click down all the way and are raised on the rear edge.
My own bike had this problem. I fixed it by removing some of the sliding plates in the lock mechanism so it could turn all the way. But this means my fuel filler could probably be opened by anyone with minor lock-picking skill and a bent hairpin or paperclip.
Does anyone know how to fix this properly?

Re: Fuel filler caps not seating correctly, How to cure it!?

Posted: Sat Aug 05, 2017 7:16 pm
by kb75ts250
Are you talking about the locking gas caps with the diecast latch? If so, the lock and pivot mechanism and spring loaded seal mechanism tends to get sticky and a shot of Tri-Flow might fix you right up.

Re: Fuel filler caps not seating correctly, How to cure it!?

Posted: Sun Aug 06, 2017 9:56 am
by sportston
kb75ts250 wrote:Are you talking about the locking gas caps with the diecast latch? If so, the lock and pivot mechanism and spring loaded seal mechanism tends to get sticky and a shot of Tri-Flow might fix you right up.
Yes I am. I don't know what triflow is. I guess it is penetrating oil. Unfortunately that didn't work. I'm fairly sure that it is a mechanical fault with the lock not stickiness. But I wondered if anyone knew how to prevent/fix it properly. I will give it some thought. It was ages since I rebuilt/bodged mine. I have a new rechromed fuel cap one to use now but will swap over the locking mechanism from old one to new. So I will see if I can work it out when I do that.

Re: Fuel filler caps not seating correctly, How to cure it!?

Posted: Mon Aug 07, 2017 7:21 am
by kb75ts250
Tri-Flow is a teflon lubricant spray. It seems to work especially well when plastic parts are involved, such as the white nylon bushings in locking gas caps and control cables with the plastic coated inner piece. I don't remember the locking gas caps being a source of customer complaints when these bikes were new nor any service bulletins or warranty replacements or modifications so I'm thinking the problem is either wear and/or corrosion. I'm really interested to hear how your experiement goes and what you learn.

Re: Fuel filler caps not seating correctly, How to cure it!?

Posted: Mon Aug 07, 2017 12:38 pm
by sportston
I'm fairly sure it is wear, not corrosion. I have a hazy memory of finding that the lock pins were slightly out of line. Perhaps that is due to wear. I'll have a look tomorrow. It is my day off then.