Saturday 29 June 2024

Zen and the Art of Motorcycle Maintenance: Patience with C14 Forks

 When I was younger I tended to struggle against time, but as I get older I'm finding that if I slow down and let go of that youthful mania I can see things that get missed and this makes me a better mechanic. Taking on the leaky forks on my 2010 Kawasaki Concours 14/1400GTR also seemed like something too complicated to get into in the garage after the much simpler right-way-up forks on the Tiger (which I get in and out of easily).

Like everything else on the Concours, the front forks are complicated. These would be the first USD (upside down) forks I've done after many right way up forks on dirt bikes and the Tiger, so I went looking for how-tos and was met with a wall of incompetence, both in video making and mechanical ineptitude. So bad were some of them that it made the job seem impossible, but it really isn't.

I finally found Coulda Shoulad Woulda's C14 Fork Seal video and it was just the thing. Yes, I'm starting you 25 seconds in because that's one hell of an intro:


Nicely edited and concise (other than that intro), oh that all youtubers took heed. After watching I believed it possible, so out to the garage I went... and was promptly beaten by the bolts on top of the forks which would not move despite a trip to Canadian Tire to buy the long 24mm socket needed to get on them properly. That socket promptly started rounding them. I suspect whoever was in there last didn't believe in torque wrenches.


Everything I needed for the job was $200 taxes
in on Amazon. The tools seem well made and
worked. The fork seal driver also came in
handy when clamping the fork on the bench.
I applied heat and kept at it, but they would not move, so after lots of sweating and swearing I
stepped away and emailed the local Kawasaki dealer, who I tend to stay away from because whenever I contacted them they give the impression that I've interrupted and annoyed them. A terse reply the next morning that was not forthcoming with the details I needed showed that their service department remains firmly of the mindset that they are doing me a favour whenever I pay them exorbitant fees for service. I finally got out of them that it's $375 to service forks out of the bike and they would only use Kawasaki parts so the seals I'd bought for the job I'd have to buy over again at their markup. A conservative estimate for the job would be $500 in service, parts and taxes, but probably more.

That took me back to the garage where, to my astonishment, the tops came off easily after a few sharp taps with a big socket and some more heat applied. If at first you don't succeed, step away and perhaps after cooling down you've already won. As Classic Bike says, 'heat and patience.'

With the tops loose I was off to the races. I applied some
intentionality to my process and decided to do a fork each day after work rather than trying to do them all at once. This paid dividends because the first fork was a learning process, and when I left it for the night I thought it over and the second one went twice as quickly with fewer problems. Taking your time and moving intentionally is an underappreciated skill in our manic, modern world.

The process of dismantling the forks is fairly straightforward, but requires some jiggery pokery around compressing the spring to get to the internals. Here are the order of operations assuming you've already removed the front fender and wheel:
  • Loosen the fork tops while they're on the bike! This isn't easy as the handlebars are in the way. I removed them for access. I also found the metal quite soft. I went out and got a long 24mm socket but it made a mess of them. A well placed vice grip while clamped on the bench did the job better.
  • Remove the fairing plastic cover over the front wheel
  • Undo the plastic cover at the top of the fork tree (three 10mm bolts) and remove the horn as well which is attached to it
  • Loosen the lower fork clamps
  • Loosen the upper fork clamps
  • Slide out the forks (this was also a pain in the ass - I ended up using a long screwdriver to gently open the clamps a bit to let the forks drop
That gets you to the point where you can start working on the forks themselves.
  • Undo the loosened fork tops (if you're luckier than me and the cock womble who was in there last didn't tighten them to death)
  • Install your fork compression tools. There are holes in the plastic spacer at the top for you to put a rod in and use the axle mount at the bottom for the other rod
It looks complicated but this is just the fork compressor clamp and a bottom rod provided in the Amazon kit being compressed with rachet straps. 


  •  With the spring compressed you will see the nut at the bottom that holds on that top piece
  • Pull up on the top piece and you should have just enough space to slip the spring holder piece (also in the Amazon kit) in place. This allows you to loosen the bottom nut and spin off the top

  • With that off you can release the rachet straps and remove the spring
  • Remove the tube from the centre of the unit. It's fragile so put it somewhere safe and then don't forget to reinstall it (don't ask)
  • Empty the oil into a container that lets you see how much is in there. Be sure to work the internals to get everything out
The side with the leak (on the right) had less in it, but both were low. There is supposed to be 550ml of oil in each fork. The dark green stuff on the left looked to be completely different to the brown stuff on the left. I'd guess whoever tried to get into these last couldn't get into one of them and just serviced the one they could - which is nuts!
  • Separate the outer fork from the inners
  • This lets you pop off the outer seal
  • The inner is held in by a retaining ring that's easy to pop out
  • Ease the fork seal out of the tube (I applied some heat as the old ones were rock hard - this softened them up a bit and made removal easier

  • With everything cleaned up, slide the outer seal on the inner fork making sure it's the right way around
  • Install the inner seal in the large (upper because these are USD) fork tube. Doing this while it's separated is much easier than trying to hammer it in when they're attached. I had no trouble getting the inner fork tube on once it was installed (the holes in the inner shaft are chamfered so sliding them on is straightforward
  • Don't forget to install the retaining ring after you've got the inner seal in (letter side down because these are USD - the 'open' side should be facing the oil).
  • Install the inner fork in the outer with new seals
  • Put the spring back
  • Put the plastic bit on top and rebuild your spring compressor (don't forget the metal cap)
  • loosen the nut on the threaded inner rod and use a matching bolt to give you something to pull it up with when you've got it back together
  • Compress it all down again with the ratchet straps
  • Pull the top using that bolt you put on and slip the metal piece to hold it in place
  • Remove the bolt you used to make it reachable and tighten the nut on the inner threaded piece that's held by the tool you slid in to hold it compressed
  • Insert that inner rod you put aside earlier (no, really, remember to do that)
  • Screw on the fork top piece and tighten to the lower nut to it
  • Double check that you've put all the bits back (inner rod, metal cap on top of the plastic top piece)
  • Press down on the compressor that's in the holes in the plastic and slip the retaining metal tool out
  • Release the rachet straps
  • Put 550ml of fork oil in each. I used 15 weight Maxima
  • Work the fork to get any bubbles out (I also let them sit overnight to let things settle)
  • Spin the outer fork onto the now attached fork top threaded piece
  • Reinstall the forks. The lower bolts said 30 Nm but they still gave me headaches when one sheered in the tube. I stepped away and sorted it out the next day when I wasn't annoyed.
This seems like a handful but if you work your way through it one step at a time it all makes sense. The first fork took me a couple of hours to take my time going through. The second one took less than an hour. Once you've done this once you'll feel able to do it again. Give Coulda Shoulda Woulda's video a watch and you'll have what you need to get it done... and be patient!

Yep, that's a broken lower fork clamp bolt sheered off inside the housing. I ended up getting it out by getting needle nose pliers on the end sticking out and spinning it out that way. This job fought me at every step, but it's all back together with matching (clean) oil in both forks and everything one tightened (to spec) not too tight. One tight, not too tight...


When things went wrong (and the did... often) on this job, I got myself to a reasonable stopping point and stepped away for the day. When I came back the seemingly insurmountable problems (stuck fork tops, broken bolt in the lower clamp) all seemed to have answers.

The old seals were rock hard. I'm curious to see how nice the forks feel with the new ones.







Vice grips did a better job on top fork removal than the specially purchased long 24mm socket did. Applying heat was easy in the vice and the seal driver tool was handy for clamping the fork off the bike.

Removing the handlebars didn't help with loosening the tops of the forks. Hat and vice grips on the bench finally did the trick. I'm going to try the handlebards without the bar risers for a while and see if it feels ok.