Introduction
This is a long how-to and explanation series of postings written by “Maxtog” for the zggtr.org forum.  I tend to be long-winded, but I think this information will be very helpful to other C14 owners.  I will attach a PDF (of a LibreOffice odt text document) of the entire thing.  But I will also post this as a multi-part text w/photos in the forum so it is searchable.

Background
Many of us have had problems with the gas cap corroding.  The symptoms are that it gets more and more difficult to open the cap.  Turning the key gets harder and harder.  Some will blame the cylinder (lock/key/key hole) others the latch on the bottom.  Often is is both.  A visual inspection will show lots of white debris and/or dark debris on the various parts.  I believe the main problem is usually the latch, which is exposed to gas vapors all the time.  This is discussed in this thread:  http://zggtr.org/index.php?topic=20069.0  The photos were lost during the forum conversion and can be seen when I reposted them years later in the same thread here:  http://zggtr.org/index.php?topic=20069.msg313558#msg313558  The thread also discusses the latch modification such that the cap can be closed without using the key (by default, it will not allow closure without using the key to pull back the lugs).  It is a simple mod to file two of the latch components such that the slot in them are about twice as long.  I strongly recommend reviewing that thread first, especially looking at the photos.

Problem Evolution
After having taken apart and cleaned/lubed the assembly many times, I came to the conclusion I  wanted to at least replace the latch.  Mostly because it seems like each time I went through this task, the result lasted fewer and fewer months.  Some of the corrosion (and resulting wear) seems permanent over time.  Unfortunately, the latch isn’t sold separately.  You can only buy an entire gas cap assembly (which has no cylinder).  I didn’t want an aftermarket, which would either have no lock function (loss of security), or some different key (loss of convenience).  So I decided after 11 years to replace the whole thing with OEM.

Replacement Part
When searching for a replacement for my 2011 assembly, I discovered the part is 51049. Kawasaki will revise parts over time and there are three revisions of the gas cap.  The original revision of the part (2008-2009) was 0012.  Then 2010-2019 was 0039  Then 2020+ is 0744.  The only currently available part is the last revision, 51049-0744.   One would hope that later revisions have improvements, but Kawasaki doesn’t release information as to what changes in revisions.  In any case, all C-14’s use the same part.  I ordered it from Partzilla for $118.04.  Part location is here:  https://www.partzilla.com/catalog/kawasaki/motorcycle/2021/concours-14-abs-zg1400emfnn/fuel-tank  part order page is here: https://www.partzilla.com/product/kawasaki/51049-0744?ref=24969e9f3dd9172306c12a0dc80bfbff5dad3daa

Part Arrival/Examination
One of my worries is that the trim ring around the cap would arrive unpainted.  But it did come with the stock, bright silver finish.  I am not sure, but I guess all years/colors of the Concours use this color.  It arrives with two short hex bolts, at (2and 10 o’clock) already installed in the trim ring (the other 4 were empty and the holes unthreaded).  The cap assembly does not come with any instructions on how the cap is disassembled, and it contains a lot of small parts.  When disassembled, these parts will often fly out all over, and some are critical for the sealing of the assembly and proper function of the venting of the tank.  The factory manual has no information either.  And, worse, after searching the internet for hours, I could find exactly zero information about all the parts of the cap and cylinder.  So it is apparently up to me to figure it all out and document it.  And that is part of what this thread is about.

Warnings
WARNING: you must be very careful when disassembling the cap when removing the two Philips screws on the latch.  If you are doing this over the gas tank, you must seal the tank hole so the parts are not lost!  If you lose a part in the tank, especially a plastic one, you are in for a world of hurt.  If you are careful, when you remove those two screws, you can hold back the rubber boot and keep all the other parts from coming out while only getting the latch and latch plate it sits on.  This can be OK if all you are doing is servicing the latch and you are very careful.  Otherwise, it is recommended you remove the whole gas cap assembly and work on it in a controlled environment.

WARNING:  The gas cap plays a critical role in keeping the proper pressure in the tank.  If it is not correctly assembled, the vacuum in the tank can increase so much with the fuel pump removing fuel that it can actually crush the metal tank.  It might also damage other parts as well.  Theoretically a defective venting system can also trap pressure when the gas is cold and then heated up by the bike or sun, causing leaks or excessive pressure on the cap.

Main Disassembly
Unlock the cap and pop it open.   Stuff a rag in the tank hole.  Remove the 3 hex bolts on the trim ring at 2, 6, and 10 O’clock.  (Do not remove 4 or 8 O’clock).  The entire assembly will now come off.  Flip it upside down and place on a flat, clean well-lit work table preferably on a towel that can catch any parts and prevent scratching/damage on the trim side.  Also a place where there is no wind and no cats or other forces of nature that would like to apply entropy to your project.  I also recommend having a magnetic tray handy.

Remove the two Philips screws in the latch that hold the assembly together.  Hold the assembly together while removing the screws.  The latch and latch plate will come off but continue to hold back the boot.  Inside the latch assembly are two plungers and two springs that fit inside the track assembly and covered by the back plate.  Try to examine them closely so you will be able to reassemble them again.  Below the assembly is a rubber/silicone boot.  When you pull off this boot, you will find six small springs around the circumference.  Take note of the venting hardware on either side of the cylinder bottom.  These contain plastic pieces and bushings.  On the new part, they will readily fall out and apart.

With the latch removed, you can now insert the key and try turning and you will now know just how much of your problem was the latch and how much was the cylinder.  In my case, the cylinder effort was far worse than the latch.

Cylinder Removal/Installation
The cylinder is one of the most challenging aspects.  It is held into the gas cap with a sliding wafer (pin, some might call it).  Once you have access to the back of the cylinder, there is a cap that covers it that must be removed.  It has two round studs on the bottom that push on the latch mechanism.  It is pressed in and has a rubber gasket.  It is designed to pull directly out.  However, if it is like mine, it was severely corroded and very difficult to move.  Unfortunately, there is little to grab ahold of, other than the two short, round studs.  And the metal is easily damaged.  There is a black rubber/silicone seal around the cylinder barrel.  Use a very tiny flat screwdriver to pry it out.  This might take a while, it is several mm thick and probably won’t cooperate.   I had to drench the back and front of the cylinder with WD40 and keep wiggling it and then could pry it out.  Then used a tiny implement to scoop out all the gunk and more WD40 and wiggling.  Then I used a large pair of vice grips to grab the two short round studs and pulled and pulled and it finally came off.

Then, do yourself a favor and perform yet more cleaning.  If done right, you can finally see a large brass wafer pin that has a dip in the center.  This sliding pin is what holds the cylinder into the cap.  Use a small screw driver, starting in the dip and slide it over to retract the sliding pin and the cylinder will come out the top of the gas cap.

[continued]

You will want to perform a thorough cleaning of the cylinder, probably with a solvent like WD40 or acetone, while also driving the key in and out.  This is necessary to remove all the old lubricants.  In my case, it was a lot.  Reinstalling the cylinder is a bit tricky.  You have to start inserting it at an angle to compress the retainer slide pin.  I can’t document exactly what I did, because with some wiggling and playing (without using the key) it eventually just fell in.  You then have to put the cap back on.  Refer to the photos to see the orientation.  Once it is inserted, carefully push the gasket washer down to seal the area.

I decided not to do the latch modification to allow closing the cap without the key.  I might do this to the new cap (like I did the old cap) later.  For now, I just want it to work and be as “factory” as possible for a while.

Reassembly
With the cylinder installed and working and the cylinder cap on, you can put the rest of the cap back together.  Make sure that the parts of the venting system are still present and installed correctly (refer to photos).  Place the 6 springs back on the pegs.  Assemble the main cover as follows.  First the metal ring with grooves down.  Place the rubber gasket on top of it, so the wide flange is facing up.  The place the plastic cap on top of that with the 4 holes toward you.  Orient it such that the small hole that does not have screws going in it is to the right, when the hinge of the assembly is at 6 O’clock.

Place the latch assembly on top of the main cover to line up the screw holes, plate down. There is a slight dimple to indicate which orientation.  Then tighten the two screws.

If you are installing a new gas cap (not replacing an existing one), take note that there is a small, round, 12mm gasket on the underside at 7 O’Clock.  This part is NOT included in the new gas cap assembly and must be moved to the new assembly before installation.  It provides a seal with a metal tube on the tank.

WARNING:  Before closing the gas cap on the tank, TEST IT AGAIN A FEW TIMES to make sure the key and latch are working correctly.  If they are not and you close the cap, you will NOT be able to open it ever again without drilling out the cylinder!

For me, the results were simply amazing.  Finally almost no resistance to opening and closing.

Lubrication
Most of my focus in the past has been on the latch- cleaning and lubricating it.  And that does solve the majority of the issue with this cap becoming stiff over time.  However, the cylinder plays a role as well.  And if you, like many people, have shot various lubricants in the cylinder over the years, it is likely to gum up the works and will need cleaning.  So if you plan to really clean the assembly, it requires also removing the cylinder to clean that, too.  And if you are replacing the whole assembly, you will need to either order a new cylinder and then either rekey it to match your ignition key, leave it on a separate key, or you will want to clean and move the old cylinder to the new gas cap.

One of many discussions is what to use as the correct lubricant for both the latch and also the cylinder.  First I will discuss either dry or wet graphite.  Don’t do it, not for the lock nor the latch.  Although graphite can be a great lubricant for some types of locks, those in a vertical orientation and especially around gas and in a wet environment is not a good combination.  For one, it is messy as hell.  And over time, it will gunk.  And if it gets wet or you use some OTHER wet lubricant later, it will make things worse.  I believe that WD-40 and regular light oil are also not good because they leave too much residue and will attract debris and the inevitable corrosion.  Same for using lithium grease on the latch.  After much research, I decided I will use a dry teflon spray (PTFE).  It is almost no mess, attracts no debris, lubricates well, is very inert, supposedly leaves a film of anti-corrosion, and lasts a long time. 

Of course, when I went to try and get some, nobody had any (typical).  Since I didn’t plan well, I decided to just blow out the WD40 from the cylinder, not lube the sides of the cylinder, and just leave the factory oil lube in the new latch.  I will revisit it later if/when needed.

[END]

PDF version attached to this posting.

Thanks, Max.

Excellent write up, Max.  Anyone considering switching out their gas cap will now have everything they need to complete this job with confidence. 

Thanks!

Excellent write up, Max.  Anyone considering switching out their gas cap will now have everything they need to complete this job with confidence.

You are welcome.  It should also be extremely helpful even if you don't want to switch a cap, but just repair or clean your existing one, or put it back together correctly.  I find it amazing zero info like this was available anywhere.

The irony is, I was unwilling to mess with the cylinder in the old cap without having a replacement cap for fear of messing things up and being left with an unridable bike for a long time.  But the problem really was mainly the cylinder and not the latch.  And that was reused and not new.  It was a reasonable mistake considering that in the past, most of my problems really were with the latch.  Yet I don't regret the decision.

1) I didn't mention it in the document, but the vent hardware in my old cap was quite messed up.  The teardrop plastic part that is supposed to move was "welded" down and couldn't be removed at all.  So that might have been dangerous.

2) Certainly the latch was far from ideal, and now it is new.

3) Some of the filler ring was cosmetically messed up from springs on gas pump nozzles, so now it is pretty again (and I hope to keep it that way).

4) The main seal was pretty worn, so now that is new.

5) The cylinder cap and seal were really bad in the old cap.  So now those are new, and were contributing to much of the problem with the cylinder.

6) I learned a lot and have more spare stuff at my disposal.

Nice write-up, sir. Looking at your pictures, I would think that the locking wafer may be able to be actuated from outside the bike. Interesting. I kinda want to take mine apart and see if I'm right.

Nice write-up, sir. Looking at your pictures, I would think that the locking wafer may be able to be actuated from outside the bike.

I don't think so.  There is no room for a tool beside the cylinder from the top

Thanks max. The pdf is in the file.

Glad to see you again...