R6 upside-down fork oil and spring change - how do?

[anparkinson]

My 05 R6 has the upside down forks.

The fork oil has never been changed so it needs to be done. How do I do it? Do I have to remove and disassemble the forks or can it be done with forks in place?

I only weight 132lbs / 60KG so want to fit softer springs. How easy is it to change the front springs? Is it worth doing when changing the oil if I have to strip them right down?

[shnormo]

Inverted forks.



Parts:
New crush washers #9
Yamaha 01 Fork fluid or equivalent
Springs
Fork Seals #21,22,23

Tools:
Rear stand
Motorcycle jack or Front Head Stand (not the one with pins or fingers that hold onto the bottom of the fork)
Sockets and allen wrenches
Spring compressor tool
Small screw driver or pick
Seal driver
Graduated Cylinder

You can actually leave the forks in the triple tree clamps for this.
I would recommend changing out the seals while you're in there as well.

Lift the rear of the bike with the rear stand. Lift the front of the bike so the forks hang freely.

Unbolt fender, brakes, and remove wheel. Directly on the bottom of the fork there is an allen bolt, remove it to drain fluid and release the cartridge. This bolt may be a little bit difficult to move. The whole cartridge will want to spin with it. I used a 3/8" to release it.
Once bolt removed, move fork up and down to drain cartridge.
Next remove the cap at the top of the fork (the larger hex). Once that is loosened you can remove the cartridge.
You will need to use the spring compressor to gain access to the retainer that holds the spring. Remove retainer and replace spring. Install in reverse order.

Fork Seals, CAREFULLY pry the outer dust cap off. Remove seal retaining clip. Make sure the bike is fully supported and sturdy because you will want to use the bottom leg like a slide hammer to pop the old seal out. Place new seal on bottom leg and reinstall into the upper fork tube. Using a seal driver carefully drive the seal into the top tube until it bottoms out and the grove for the retaining ring can be seen. Reinstall the retaining ring and dust shield.

Slide the cartridge back into the fork. Put the new crush washer on the drain bolt. Push the lower fork leg up and insert bolt (this makes the hole line up easier). Fill with Yamaha's 01 or equivalent fork fluid I believe it's .5L per side. Then before screwing the top cap on, work the bottom fork to release air bubble and to get fluid back into the cartridge. Tighten the top cap, reinstall fender, brakes, and wheel. You're all done

[anparkinson]

Thanks. This helps a lot.

[luke geis]

the spring will be difficult without proper tools. you will need a spring compressor to change the spring. Outside of that there are things on you tube about how to change just the oil.

[RUFFSTUFF]

Thanks!

[Colin]

Hey, thats damn helpful! Thanks!

A couple questions though:
Is it a specific spring compressor that you need?
Exactly what size is that big hex nut on the top of the shock? 41mm?
And where the hell does one get a seal driver? lol

[shnormo]

Yes there is a specific spring compressor that you will need. It is a tube that has two holes and handles. You put it over the cartridge and put the pins into the spring spacer under the retainer so you can put preload on the spring and remove the retainer.

I don't remember off the top of my head what size the fork tube cap is.

You can back yard mechanic make fork seal drivers. Take PVC pipe and cut it in half along with the old seal and use that to drive the new one in.
Motion pro makes affordable ones also
Motion Pro Bullets

[Colin]

Excellent, thanks again Shnormo.
I'm lookin around town right now to see if I can scrounge up a wrench that will fit.
I might even do up a how-to out of this! We'll see if it works.

I just can't bring myself to pay shop rates on shit I can do mysef!

[DanQ]

The fork oil should be 92mm measured with the tubes collapsed, and the springs removed. Generally you will put approximately .502 US qt of oil in each leg, but it must be measured after after the cartridges are bled.

The work is not hard, but if you don't have the proper tools, leave it to someone who does.

Oh... and I would not do forks in place in the triples. Unlike most dirt bikes and other forks the tubes on these Kayabas can slide apart (there is no stop on the inner tube) and ruin the seals and potentially damage the inner tube if it falls.

[DanQ]

Originally Posted by Colin

Hey, thats damn helpful! Thanks!

A couple questions though:
Is it a specific spring compressor that you need?
Exactly what size is that big hex nut on the top of the shock? 41mm?
And where the hell does one get a seal driver? lol

24 mm. Remember when reassembling this should only be torqued to around 7 lb/ft.