Anyone change their fork oil at a regular interval?

So, in with doing my spring maintenance I decided to change the fork oil. My bike is a 05 FZ6 and I have had it since June 2010 at which time it had 7200 miles. This spring it is at 23k and change. I can say with relative confidence that the fork oil had not been previously changed, and i didn't realize how dirty it becomes. I say this as I have the original bill of sale and all maintenance receipts from the previous owner. :rockon:

All I could find in the service manual and owners manual was to inspect and check for leaks. Seems like this should be an item on the scheduled maintenance list, or am I going blind. From some online research, this seems to be a topic for debate but most say it should be changed (yearly, every oil change, every other year, etc.).

All I did was take the forks off, turn them upside down, let them drain and pump them a few times by hand. Refilled with 5w fork oil. I suspect at some time I will have to replace the seals, but they are not leaking.

Note: Yes the oil has something it it that makes it form the funky colors but I did not find any signs or moisture in the oil or signs inside the forks.

Also, the new oil is clear so we will see how it looks next year.

Its my observation that the first 5000 miles makes a fair amount of metallic bits and then it could be done every 2 to 3 years or roughly 15,000 ~ 20,000 miles.

JM2C, but springs and the stanchion tube have a rough finish and their initial "wear in" makes allot of metal debris. Once through that wear in, it appears to decline sharply. A few months back i dumped two year old oil out with 13,000 miles on it and it looked very clean.
The manuals never seem to reference this.

I changed mine for the first time at a little over 5000 miles, and it looked like crap.

I guess i will change it every 7000 miles or so. Once you have done it once it's pretty quick and the oil isn't to expensive. Might as well do it!

I just bought a 2005 with a little over 6k miles on it and my fork oil looked just as dirty as yours!

Is that the procedure (i.e. take the forks off) or can they be drained and filled without disassembling them from the bike?

ltdillard said:

Is that the procedure (i.e. take the forks off) or can they be drained and filled without disassembling them from the bike?

Click to expand...

yes, you have to take the front wheel off and remove the forks.
It is theoretically possible to do this w/o removing the front wheel (if you raise the front of the bike considerably and pull the wheel/front forks as one piece - i've done that when i changed head bearings, but if you are opening up the forks, you may as well look at the front bearings, so I'd recommend a centerstand + weight on the back and removing the front wheel.

I'm due to change mine. I don't see the point in not changing the seals if they are over 5 years old. Seals deteriorate. Might as well if you are going through the trouble of disassembling the forks anyway.

ltdillard said:

Is that the procedure (i.e. take the forks off) or can they be drained and filled without disassembling them from the bike?

Click to expand...

Some people have used a vacuum pump and just pumped the oil out from the top.
Problem is you won't get all the crap lying at the bottom, and you cannot cycle fresh fluid a couple time to really clean things out.

Considering you can change the oil in 2 hours removing the front wheel and the forks i wouldn't bother half doing it with a pump.

I too have an 05 with about 22k miles and I replaced my fork oil last week in preparation for this years riding season. The reason I did mine was to change to a thicker oil (I replaced mine with 15wt) to take some of the bounce out of the front. I am under the impression that the FZ6 was designed for a 180ish pound rider and I am about 220 with gear.

The oil I drained looked exactly like yours, but I have no indication that it needed replacement. I am guessing that removing the small bits of metal that mix into the original oil is not a bad idea, but other than that I did mine as an upgrade, not maintenance or repair.

And to anyone asking about the difficulty, if you have the skills and tools to remove the front wheel then the forks will not be hard. The funniest part was removing the upper cap, knowing that the spring will push it up once unscrewed. Every thing I read and every video I watched said to be careful that the spring doesn't fly out. I've worked with automotive springs and know the dangers of a spring set loose. So I had the fork tube in a vice and was unscrewing the cap slow and deliberately, like I was opening up a nuke. I had my feet apart and my shoulder over the cap, ready to man-handle that spring. Once the cap was off, the spring released with about the same pressure as opening a can of flat soda!

trepetti said:

And to anyone asking about the difficulty, if you have the skills and tools to remove the front wheel then the forks will not be hard. The funniest part was removing the upper cap, knowing that the spring will push it up once unscrewed. Every thing I read and every video I watched said to be careful that the spring doesn't fly out. I've worked with automotive springs and know the dangers of a spring set loose. So I had the fork tube in a vice and was unscrewing the cap slow and deliberately, like I was opening up a nuke. I had my feet apart and my shoulder over the cap, ready to man-handle that spring. Once the cap was off, the spring released with about the same pressure as opening a can of flat soda!

Click to expand...

Really? I've never heard that fork springs can be under tension when the forks are off the bike. That's kinda the point. With no weight on the fork the spring should be fully extended, thus no tension.

I'll be doing my forks soon. Where did you get your fork oil? Do you remember how much it took for each fork?

trepetti said:

The funniest part was removing the upper cap, knowing that the spring will push it up once unscrewed. Every thing I read and every video I watched said to be careful that the spring doesn't fly out. I've worked with automotive springs and know the dangers of a spring set loose. So I had the fork tube in a vice and was unscrewing the cap slow and deliberately, like I was opening up a nuke. I had my feet apart and my shoulder over the cap, ready to man-handle that spring. Once the cap was off, the spring released with about the same pressure as opening a can of flat soda!

Click to expand...

I did that this past weekend. My dad was helping me and he (being a diesel engineer by education and coming from Russia) was suggesting all sorts of ways of how to open it carefuly, including and not limited to building a purpose-built guide that would allow a slow controlled opening. I know one day this will come back to bite me, but i got a good laugh when i opened it in front of him.

FIZZER6 said:

Really? I've never heard that fork springs can be under tension when the forks are off the bike. That's kinda the point. With no weight on the fork the spring should be fully extended, thus no tension.

I'll be doing my forks soon. Where did you get your fork oil? Do you remember how much it took for each fork?

Click to expand...

There is a slight pre-load with the forks fully extended....VERY slight.

I purchased Maxima fork oil from Amazon. Prices were good, free shipping, etc. The manual calls for 0.49 qt per fork leg. I purchased 2 quarts so that I could fill and flush each tube once before the final fill.

FIZZER6 said:

Really? I've never heard that fork springs can be under tension when the forks are off the bike. That's kinda the point. With no weight on the fork the spring should be fully extended, thus no tension.

I'll be doing my forks soon. Where did you get your fork oil? Do you remember how much it took for each fork?

Click to expand...

Yeah, same here, mine barely had any tension once the fork was extended.

It actually had a lot more tension with the new springs and the new spacers.

Fork oil quantity is 467 cm3, meaning you should have enough with 1 liter, or even a quart.
Although i would get a little bit more so you can use some to flush the fork. Fill it a bit, pump it a few time, empty, fill again, pump, empty, it helps clear the crap out.

The final level should be measured, it should be 134mm from the top of the fork tube to the oil surface, with the fork compressed fully and no spring or spacer.

trepetti said:

I purchased Maxima fork oil from Amazon. Prices were good, free shipping, etc. The manual calls for 0.49 qt per fork leg. I purchased 2 quarts so that I could fill and flush each tube once before the final fill.

Click to expand...

Thanks for that tip. I had just ordered a 1 liter bottle (2 qts) to change the oil this weekend...but the idea of flushing the tubes sounds like a great plan. Added another 2 Qts to the order!

Ohendo said:

Thanks for that tip. I had just ordered a 1 liter bottle (2 qts) to change the oil this weekend...but the idea of flushing the tubes sounds like a great plan. Added another 2 Qts to the order!

Click to expand...

Something not right here!

1 quart is a tiny bit more than 1 liter...

Anyway, 2 liters should be more than enough, i had two liters when i did mine and ended up with half a liter left after flushing.

Carlos840 said:

Something not right here!

1 quart is a tiny bit more than 1 liter...

Anyway, 2 liters should be more than enough, i had two liters when i did mine and ended up with half a liter left after flushing.

Click to expand...

Good catch. Bad math.
I ordered a 1 liter bottle (~1 US Qt), which would generally be enough to do both forks. So I ordered another to be able to flush liberally.

Ohendo said:

Good catch. Bad math.
I ordered a 1 liter bottle (~1 Qt), which would generally be enough to do both forks. So I ordered another to be able to flush liberally.

Click to expand...

No worries, just wanted to make sure you didn't end up with 4 qts and a lot to much oil!

Typically the lower spring rates will be a longer static free length while the higher rates will be a physically shorter spring (you don't have to pre-load them as much to get the proper sag). So top cap removal is less of an issue as the rates go up. But no, the spring is not going to tear your head off much less give you a work out.

Please - while taking care to change your fork oil, check the SAG and adjust it.
Also, bikes with the center stand in place, just through a block of wood under the headers when doing fork work. Its quick, easy and effective.

As mentioned by Carlos, remove the forks, dump the old fluid, and then cycle NEW CLEAN fluid through the fork is the best bet towards removing sediment from the fork tubes. Sucking the fluid out just seems like a waste of time as your leaving all that sediment behind.

Besides, pulling the the nose apart and inspecting everything is really in your best interest so you as the owner and mechanic know the condition of your bikes hardware, clamps tight, caliper tight, bearings inspected, etc.

Just replaced the fork oil yesterday, it was nasty! I put in fresh 7.5 wt synthetic. A vast improvement from the oem, next is some race tech springs, or full r6 front...next year

GS3

Changed out my fork oil yesterday, and mine was super nasty as well. Some sort of gray slurry-type crap. Flushed several times with clean oil. Also found out that the springs were installed upside down by PO vs what the manual says, longer spring coil distance portion was on top. Not sure how that would make a difference though.

Thanks to an Amazon hiccup on my Maxima order, I obtained my new fork oil from ** gasp ** the local HD dealer. Price was fair, and all of the non-HD shops were closed Monday. Had to cross reference their codes to determine "type E" was what I wanted. Just in case anyone else happens to use HD fork oil, here's the conversion:

type e - 5 wt
type b - 10 wt
se heavy - 15 wt
se race - 20 wt