Saturday, December 9, 2017

Changing Fork Seals — 2011 - 2013 Honda CBR600RR

One at a time...
So I was going for the approach here of "If it ain't broke, don't fix it".

Only the RH fork seal is leaking on the little CBR, but it's long overdue (just like tutorials on this blog). Well, no more! I haven't been riding as much because of it. I seriously needed a kick up the arse.
With front mudguard removed, you can just about see the oil on the stanchion. It was bad at this stage... luckily it's only the brake caliper down here so not a safety issue. 😂

I popped into Honda and bought a pair of seals and a litre of Motul synthetic 10W fork oil. The Honda manual suggests using Honda Ultra Cushion oil SS-8. I really would like some of that ultra cushion because it sounds awesome, but I think the Motul will be more than adequate. Yes, I'm having a giraffe.

But here's the thing. If I change the RH seal, and just refresh the oil in the left fork, will it bite me in the ass in a month's time and leak? I almost guarantee it — so I'll do them both now, and save the heartache.

Before I start disassembly, personal preference is to write down the current suspension settings, then undo each adjuster completely — especially rebound and preload adjusters. That stops any damage occurring when removing parts under tension.

Then calipers were whipped off. And wheel removed.

Always undo the fork top bolt in the triple clamps before slackening the fork top nut. The nut shouldn't be very tight, but will bind if the triple clamps are tight. Loosening it at this stage makes it a lot easier than when the fork is out too.

And in less than ten minutes I'm already forked right off.

One thing I did have to do to fit the fork on my homemade spring compressor was drill the holes in the plastic spacers out to 8mm. They are only 6mm on the Honda. I held the drill bit in a rag and turned it by hand to avoid damage inside the spacer that may have occurred with a Black & Decker turning at 3,000 RPM.
I was also being careful not to let the swarf fall inside the fork.

Once compressed you can get at the 14mm locknut and undo the 17mm flats of the fork top nut.

The rebound needle and extension rod are all in one piece on the Showa's, and stay with the fork top nut.

The Motul fork oil, and the rebound adjuster.

Quick check of the thread length sticking out above the locknut, just in case anything moves. Then the spring can be released and the forks taken apart as follows:

1) Gently pry the dust seal from the outer tube, and down the stanchion to give access to the circlip on top of the fork seal.
2) Take that out with a small screwdriver, and then pull both parts of the fork apart. It will meet quite a bit of resistance as it pushes the fork seal out. But a few sharp pulls and it should come apart.

With the two bushings carefully removed from stanchion, followed by the washer, fork seal and dust seal. We can get it ready for the new ones. 

I'm cleaning up my old dust seals and refitting them. Make sure theres no dirt inside them or you'll ruin your new fork seals.

Once the stanchion is clean, tape up the top so the seal doesn't get damaged sliding it over the tube. The writing on the seal faces the bottom of the fork (the side with the opening goes up into the outer fork tube). Grease or oil will also help get them on without damage. 

Put your dust seal back on first, then your new oil seal. The washer goes on next, followed by the first bush. Then the top bush slides over and sits where my insulation tape is in the pic. 

I used this colour tape so I was earthed in the event of lightning, honest.

Now for reassembly. Dust seal at the bottom, circlip, new seal with washer resting on top, followed by the lower fork bush.

Any excuse to buy new tools. Sometimes it's just better to have the right kit. And Motion Pro stuff is awesome! 

With seal driver assembled over the stanchion, it's time to push the seal home. Because I'd smeared rubber grease on the seal, firm pressure was enough to push it into position. This is preferable to having to keep bashing it down until it seats.

With the seal fitted correctly, push the circlip back into place. If the seal is seated correctly, it will snap into place with ease. If it's met with resistance, there's a good chance the seal hasn't been pushed fully home. 

Once it's in, push the dust seal back into place and pour the necessary amount of oil into the top of the fork. For the 2011 - 2013 CBR, without ABS, it's 413ml. ABS models take 416cc. 
Next, pull the cartridge inner tube up and down to bleed the fork of air. If the tube goes slowly but then falls with no resistance, there is still air in there. 
Take your time and continue to pump until resistance is felt all the way through the stroke. Leave it ten minutes for everything to settle and then measure your air gap. This is done by setting a tube at the required length and sucking the excess oil out with a syringe. 
For the non-ABS model it's 93mm from top of fork to where the oil level is. ABS models are 90mm.

Pop the spring back in, along with spacer and compress until you can screw the fork top nut back on. Once everything is locked up correctly, get them back in that bike and start adjusting the settings. Probably as well to go with standard settings and then work from there. 

Get a new zip tie on your stanchion to gauge how much travel you're using and road test. The Showa's on these don't go all the way down under normal use, due to their oil lock stops, so mark a line on the stanchion about 25mm from the bottom. The zip tie will let you know how much of the available travel you're getting.

Now go ride!